Now that #149310 has restricted lifetime intrinsics to only work on
allocas, we can also drop the explicit size argument. Instead, the size
is implied by the alloca.

This removes the ability to only mark a prefix of an alloca alive/dead.
We never used that capability, so we should remove the need to handle
that possibility everywhere (though many key places, including stack
coloring, did not actually respect this).

If we use `CodeExtractor` to extract the block1 into a new function,

```
define void @foo() !dbg !2 {
entry:
  %1 = alloca i32, i64 1, align 4
  %2 = alloca i32, i64 1, align 4
  #dbg_declare(ptr %1, !8, !DIExpression(), !1)
  br label %block1

block1:
  store i32 1, ptr %1, align 4
  store i32 2, ptr %2, align 4
  #dbg_declare(ptr %2, !10, !DIExpression(), !1)
  ret void
}
```

it will look like the extracted function shown below (with some
irrelevent details removed).

```
define internal void @extracted(ptr %arg0, ptr %arg1) { 
newFuncRoot:
  br label %block1

block1:
  store i32 1, ptr %arg0, align 4
  store i32 2, ptr %arg1, align 4
  ret void
}
```

You will notice that it has replaced the usage of values that were in
the parent function (%1 and %2) with the arguments to the new function.
But it did not do the same thing with `#dbg_declare` which was simply
dropped because its location pointed to a value outside of the new
function. Similarly arg0 is without any debug record, although the value
that it replaced had one and we could materialize one for it based on
that.

This is not just a theoretical limitations. `CodeExtractor` is used to
create functions that implement many of the `OpenMP` constructs in
`OMPIRBuilder`. As a result of these limitations, the debug information
is missing from the created functions.

This PR tries to address this problem. It iterates over the input to the
extracted function and looks at their debug uses. If they were present
in the new function, it updates their location. Otherwise it materialize
a similar usage in the new function.

Most of these changes are localized in `fixupDebugInfoPostExtraction`.
Only other change is to propagate function inputs and the replacement
values to it.

---------

Co-authored-by: Tim Gymnich <tim@gymni.ch>
Co-authored-by: Michael Kruse <llvm-project@meinersbur.de>

These date back to when the non-intrinsic format of variable locations
was still being tested and was behind a compile-time flag, so not all
builds / bots would correctly run them. The solution at the time, to get
at least some test coverage, was to have tests opt-in to non-intrinsic
debug-info if it was built into LLVM.

Nowadays, non-intrinsic format is the default and has been on for more
than a year, there's no need for this flag to exist.

(I've downgraded the flag from "try" to explicitly requesting
non-intrinsic format in some places, so that we can deal with tests that
are explicitly about non-intrinsic format in their own commit).

This patch makes the final major change of the RemoveDIs project, changing the
default IR output from debug intrinsics to debug records. This is expected to
break a large number of tests: every single one that tests for uses or
declarations of debug intrinsics and does not explicitly disable writing
records. 

If this patch has broken your downstream tests (or upstream tests on a
configuration I wasn't able to run):
1. If you need to immediately unblock a build, pass
`--write-experimental-debuginfo=false` to LLVM's option processing for all
failing tests (remember to use `-mllvm` for clang/flang to forward arguments to
LLVM).
2. For most test failures, the changes are trivial and mechanical, enough that
they can be done by script; see the migration guide for a guide on how to do
this: https://llvm.org/docs/RemoveDIsDebugInfo.html#test-updates
3. If any tests fail for reasons other than FileCheck check lines that need
updating, such as assertion failures, that is most likely a real bug with this
patch and should be reported as such.

For more information, see the recent PSA:
https://discourse.llvm.org/t/psa-ir-output-changing-from-debug-intrinsics-to-debug-records/79578

CodeExtractor shifts dbg.value intrinsics out of the region being
extracted and updates them to be appropriate in the extracted function.
With new non-intrinsic variable locations, we need to manually do this
too, with DPValues.

Most of this patch shifts and refactors some utilities in
fixupDebugInfoPostExtraction so that we can add a single extra helper
lambda that iterates over DPValues and applies update-utilities. We also
have to assign the IsNewDbgInfoFormat flag in a bunch of places -- this
normally gets set the moment you insert a block into a function (or
function into a module), however a few blocks are constructed here
before being inserted, thus we have to do some manual setup.

Tested via LoopExtractor_alloca.ll, which invokes debugify.

-loop-extract-single is just -loop-extract on one loop.

-loop-extract depended on -break-crit-edges and -loop-simplify in the
legacy PM, but the NPM doesn't allow specifying pass dependencies like
that, so manually add those passes to the RUN lines where necessary.

Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D89016

We should only skip `lifetime` and `dbg` intrinsics when searching for users.
Other intrinsics are legit users that can't be ignored.

Without this fix, the testcase would result in an invalid IR. `memcpy`
will have a reference to the, now, external value (local to the
extracted loop function).

Fix PR42194

Differential Revision: https://reviews.llvm.org/D78749