Not that we ever do that, because this is unused code, but if someone
was debugging lldb I guess they'd call this.

Was missed in https://github.com/llvm/llvm-project/pull/145645

Relates to https://github.com/llvm/llvm-project/issues/135208

Follow-up to
https://github.com/llvm/llvm-project/pull/145645#discussion_r2174948997

There's no need for this variable to be declared at the function-level.
We reset it in all the cases where it's used anyway.

This patch just inlines the usage of the variable entirely.

This PR introduces support for the DWARF64 format, enabling handling of
64-bit DWARF sections as defined by the DWARF specification. The update
includes adjustments to header parsing and modification of form values
to accommodate 64-bit offsets and values.
Also Added the testcase to verify the DWARF64 format.

They are left over from our previous attempt at DWARF64. The new attempt
is not using them, and they also don't have equivalents in the llvm
DWARFDataExtractor class.

This relands changes in #144424 for adding a count of DWO files
parsed/loaded and the total number of DWO files.

The previous PR was reverted in #145494 due to the newly added unit
tests failing on Windows and MacOS CIs since these platforms don't
support DWO. This change add an additional
`@add_test_categories(["dwo"])` to the new tests to
[skip](https://github.com/llvm/llvm-project/blob/cd46354dbd10820158edabe14dbd49d9f9010722/lldb/packages/Python/lldbsuite/test/test_categories.py#L56)
these tests on Windows/MacOS.

Original PR: #144424

### Testing
Ran unit tests
```
$ bin/lldb-dotest -p TestStats.py llvm-project/lldb/test/API/commands/statistics/basic/
----------------------------------------------------------------------
Ran 24 tests in 211.391s

OK (skipped=3)
```

Reverts llvm/llvm-project#144424

Caused CI failures.

macOS CI failure was:
```
10:20:36  FAIL: test_dwp_dwo_file_count (TestStats.TestCase)
10:20:36      Test "statistics dump" and the loaded dwo file count.
10:20:36  ----------------------------------------------------------------------
10:20:36  Traceback (most recent call last):
10:20:36    File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/commands/statistics/basic/TestStats.py", line 639, in test_dwp_dwo_file_count
10:20:36      self.assertEqual(debug_stats["totalDwoFileCount"], 2)
10:20:36  AssertionError: 0 != 2
10:20:36  Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
10:20:36  ======================================================================
10:20:36  FAIL: test_no_debug_names_eager_loads_dwo_files (TestStats.TestCase)
10:20:36      Test the eager loading behavior of DWO files when debug_names is absent by
10:20:36  ----------------------------------------------------------------------
10:20:36  Traceback (most recent call last):
10:20:36    File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/commands/statistics/basic/TestStats.py", line 566, in test_no_debug_names_eager_loads_dwo_files
10:20:36      self.assertEqual(debug_stats["totalDwoFileCount"], 2)
10:20:36  AssertionError: 0 != 2
10:20:36  Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
10:20:36  ======================================================================
10:20:36  FAIL: test_split_dwarf_dwo_file_count (TestStats.TestCase)
10:20:36      Test "statistics dump" and the dwo file count.
10:20:36  ----------------------------------------------------------------------
10:20:36  Traceback (most recent call last):
10:20:36    File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/commands/statistics/basic/TestStats.py", line 588, in test_split_dwarf_dwo_file_count
10:20:36      self.assertEqual(len(debug_stats["modules"]), 1)
10:20:36  AssertionError: 42 != 1
10:20:36  Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
```

The only difference from the original PR are the added BRIEF and
FULL_DOCS arguments to define_property, which are required for
cmake<3.23.

## Summary
A new `totalLoadedDwoFileCount` and `totalDwoFileCount` counters to
available statisctics when calling "statistics dump".

1. `GetDwoFileCounts ` is created, and returns a pair of ints
representing the number of loaded DWO files and the total number of DWO
files, respectively. An override is implemented for `SymbolFileDWARF`
that loops through each compile unit, and adds to a counter if it's a
DWO unit, and then uses `GetDwoSymbolFile(false)` to check whether the
DWO file was already loaded/parsed.

3. In `Statistics`, use `GetSeparateDebugInfo` to sum up the total
number of loaded/parsed DWO files along with the total number of DWO
files. This is done by checking whether the DWO file was already
successfully `loaded` in the collected DWO data, anding adding to the
`totalLoadedDwoFileCount`, and adding to `totalDwoFileCount` for all CU
units.

## Expected Behavior
- When binaries are compiled with split-dwarf and separate DWO files,
`totalLoadedDwoFileCount` would be the number of loaded DWO files and
`totalDwoFileCount` would be the total count of DWO files.
- When using a DWP file instead of separate DWO files,
`totalLoadedDwoFileCount` would be the number of parsed compile units,
while `totalDwoFileCount` would be the total number of CUs in the DWP
file. This should be similar to the counts we get from loading separate
DWO files rather than only counting whether a single DWP file was
loaded.
- When not using split-dwarf, we expect both `totalDwoFileCount` and
`totalLoadedDwoFileCount` to be 0 since no separate debug info is
loaded.

## Testing
**Manual Testing**
On an internal script that has many DWO files, `statistics dump` was
called before and after a `type lookup` command. The
`totalLoadedDwoFileCount` increased as expected after the `type lookup`.
```
(lldb) statistics dump
{
  ...
  "totalLoadedDwoFileCount": 29,
}
(lldb) type lookup folly::Optional<unsigned int>::Storage
typedef std::conditional<true, folly::Optional<unsigned int>::StorageTriviallyDestructible, folly::Optional<unsigned int>::StorageNonTriviallyDestructible>::type
typedef std::conditional<true, folly::Optional<unsigned int>::StorageTriviallyDestructible, folly::Optional<unsigned int>::StorageNonTriviallyDestructible>::type
...
(lldb) statistics dump
{
  ...
  "totalLoadedDwoFileCount": 2160,
}
```
**Unit test**
Added three unit tests that build with new "third.cpp" and "baz.cpp"
files. For tests with w/ flags `-gsplit-dwarf -gpubnames`, this
generates 2 DWO files. Then, the test incrementally adds breakpoints,
and does a type lookup, and the count should increase for each of these
as new DWO files get loaded to support these.
```
$ bin/lldb-dotest -p TestStats.py ~/llvm-sand/external/llvm-project/lldb/test/API/commands/statistics/basic/
----------------------------------------------------------------------
Ran 20 tests in 211.738s

OK (skipped=3)
```

Starting with https://github.com/llvm/llvm-project/pull/124790, Clang
emits `DW_AT_object_pointer` encoded as integer constants rather than
DIE references. This patch accounts for this.

Depends on https://github.com/llvm/llvm-project/pull/145328 and
https://github.com/llvm/llvm-project/pull/145126

This reverts commit 877511920dcf36463e06746d626e8876583a6abd.

This fixes the `TestObjCInBlockVars.py` LLDB API test.

The issue was that `GetCXXObjectParameter` wouldn't deduce the object
parameter of Objective-C method definitions correctly. In DWARF those
don't have a `DW_AT_specification` (so no link back to a DeclContext
that is a class type). The fix is to only check the validity of the
DeclContext DIE *if* no `DW_AT_object_pointer` exists on the DIE. If
`DW_AT_object_pointer` does exist, we should just always use that as the
object_parameter.