Revert the changes made in the following PRs as they are causing bot
failures:

- https://github.com/llvm/llvm-project/pull/145744
- https://github.com/llvm/llvm-project/pull/144913

`SDKSupportsBuiltinModules` always returns true on newer versions of
Darwin based OS. The only way for this call to return `false` would be
to have a version mismatch between lldb and the SDK (recent lldb
manually installed on macOS 14 for instance).

This patch removes this check and hardcodes the value of
`BuiltinHeadersInSystemModules` to `false`.

The `DW_AT_APPLE_sdk` should always be equal to the filename of the
`DW_AT_LLVM_sysroot`. We can use this property to simplify
`XcodeSDK::Merge` to no longer manually adjust the sysroot filename.
Instead we simply update the sysroot filename with merged SDK name.

This should be an NFC change.

This reverts commit 6041c745f32e8fd60ed24e29e7d919d8d1c87ca6.

Relands the original patch with the test-case data fixed. Weirldy the PR CI
didn't seem to run the unit-tests? In any case, the problem was an
incorrect expectation in the test-case data. Since we have both public
and internal SDK in that test-case, we should `expect_mismatch` to be
`true`.

Reverts llvm/llvm-project#128712


```
******************** TEST 'lldb-unit :: SymbolFile/DWARF/./SymbolFileDWARFTests/10/14' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/tools/lldb/unittests/SymbolFile/DWARF/./SymbolFileDWARFTests-lldb-unit-1021-10-14.json GTEST_SHUFFLE=1 GTEST_TOTAL_SHARDS=14 GTEST_SHARD_INDEX=10 GTEST_RANDOM_SEED=62233 /Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/tools/lldb/unittests/SymbolFile/DWARF/./SymbolFileDWARFTests
--

Script:
--
/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/tools/lldb/unittests/SymbolFile/DWARF/./SymbolFileDWARFTests --gtest_filter=SDKPathParsingTests/SDKPathParsingMultiparamTests.TestSDKPathFromDebugInfo/6
--
/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/unittests/SymbolFile/DWARF/XcodeSDKModuleTests.cpp:265: Failure
Expected equality of these values:
  found_mismatch
    Which is: true
  expect_mismatch
    Which is: false


/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/unittests/SymbolFile/DWARF/XcodeSDKModuleTests.cpp:265
Expected equality of these values:
  found_mismatch
    Which is: true
  expect_mismatch
    Which is: false
```

`GetSDKRoot` uses `xcrun` to find an SDK root path for a given SDK
version string. But if the SDK doesn't exist in the Xcode installations,
but instead lives in the `CommandLineTools`, `xcrun` will fail to find
it. Negative searches for an SDK path cost a lot (a few seconds) each
time `xcrun` is invoked. We do cache negative results in
`find_cached_path` inside LLDB, but we would still pay the price on
every new debug session the first time we evaluate an expression. This
doesn't only cause a noticable delay in running the expression, but also
generates following error:
```
error: Error while searching for Xcode SDK: timed out waiting for shell command to complete
(int) $0 = 42
```

In this patch we avoid these possibly expensive calls to `xcrun` by
checking the `DW_AT_LLVM_sysroot`, and if it exists, using that as the
SDK path. We need an explicit check for the `CommandLineTools` path
before we call `RegisterXcodeSDK`, because that will try to call
`xcrun`. This won't prevent other uses of `GetSDKRoot` popping up that
cause us to make expensive `xcrun` calls, but for now this addresses the
regression in the expression evaluator. We also had to adjust the
`XcodeSDK::Merge` logic to update the sysroot. There is one case for
which this wouldn't make sense: if a CU was compiled with
`CommandLineTools` and a different one with an older internal SDK, in
that case we would update the `CommandLineTools` sysroot with a
`.Internal.sdk` prefix, which won't possibly exist for
`CommandLineTools`. I added a unit-test for this. Not sure if we want to
explicitly detect and disallow this, given it's quite a niche scenario.

rdar://113619904
rdar://113619723

Depends on https://github.com/llvm/llvm-project/pull/102488

This reverts commit
https://github.com/llvm/llvm-project/commit/cf56e265e4b74799aee72a04b634fcc261078084.

The original change was reverted because it was causing linker failures
in the unit-tests:
```
Undefined symbols for architecture arm64:
  "lldb_private::PlatformDarwin::GetSDKPathFromDebugInfo(lldb_private::Module&)",
referenced from:
      lldb_private::ClangExpressionParser::ClangExpressionParser(lldb_private::ExecutionContextScope*,
lldb_private::Expression&, bool,
std::__1::vector<std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char>>,
std::__1::allocator<std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char>>>>,
std::__1::basic_string<char, std::__1::char_traits<char>,
std::__1::allocator<char>>) in
liblldbPluginExpressionParserClang.a[11](ClangExpressionParser.cpp.o)
ld: symbol(s) not found for architecture arm64
c++: error: linker command failed with exit code 1 (use -v to see
invocation)
```

The relanded version differs only in the fact that we now use the
generic `Platform` abstraction to get to `GetSDKPathFromDebugInfo`.

This reverts commit 1cbcf74083e92021472ec9644b88418f377ce550.

unittests do not build because liblldbPluginExpressionParserClang.a now
depends on liblldbPluginPlatformMacOSX.a when built on macOS, reverting
until we can straighten out the dependency.

This patch changes the way we initialize `BuiltinHeadersInSystemModules`
which is one of the flags controlling Clang's behaviour when the Darwin
module is split into more fine-grained modules. The
ClangExpressionParser currently unconditionally sets
`-fbuiltin-headers-in-system-modules` when evaluating expressions with
the `target.import-std-module` setting. This flag should, however, be
set depending on the SDK version (which is what the Clang Darwin
toolchain does).

Unfortunately, the compiler instance that we create with
`ClangExpressionParser` never consults the Clang driver, and thus
doesn't correctly infer `BuiltinHeadersInSystemModules`. Note, this
isn't an issue with the `CompilerInstance` that the
`ClangModulesDeclVendor` creates because it uses the `createInovcation`
API, which calls into `Darwin::addClangTargetOptions`.

This patch mimicks how `sdkSupportsBuiltinModules` is used in
`Darwin::addClangTargetOptions`.

This ensures that the `import-std-module` API tests run cleanly
regardless of SDK version.

The plan is to eventually make the `CompilerInstance` construction in
`ClangExpressionParser` go through the driver, so we can avoid
duplicating the logic in LLDB. But we aren't there yet.

**Implementation**
* We look for the `SDKSettings.json` in the sysroot directory that we
found in DWARF (via `DW_AT_LLVM_sysroot`)
* Then parse this file and extract the SDK version number out of it
* Then mimick `sdkSupportsBuiltinModules` from `Toolchains/Darwin.cpp`
and set `BuiltinHeadersInSystemModules` based on it

rdar://116490281

Upstream support for debugging xros applications through LLDB.