[clang] [LifetimeSafety] Read lifetimebound attribute on implicit 'this' from all redeclarations (PR #176188)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-flang-rhel-clang` running on `ppc64le-flang-rhel-test` while building `clang` at step 6 "test-build-unified-tree-check-flang".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/157/builds/43817

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-flang) failure: 1200 seconds without output running [b'ninja', b'check-flang'], attempting to kill
...
PASS: Flang :: Transforms/verify-known-runtime-functions.fir (4116 of 4126)
PASS: Flang :: Transforms/stack-arrays.f90 (4117 of 4126)
PASS: Flang :: Transforms/tbaa-local-alloc-threshold.fir (4118 of 4126)
PASS: Flang :: Semantics/numeric_storage_size.f90 (4119 of 4126)
PASS: Flang :: Driver/fopenmp.f90 (4120 of 4126)
PASS: Flang :: Transforms/debug-dwarf-version.fir (4121 of 4126)
PASS: Flang :: Transforms/OpenACC/acc-implicit-data-fortran.F90 (4122 of 4126)
PASS: Flang :: Driver/linker-options.f90 (4123 of 4126)
PASS: Flang :: Driver/omp-driver-offload.f90 (4124 of 4126)
PASS: Flang :: Intrinsics/math-codegen.fir (4125 of 4126)
command timed out: 1200 seconds without output running [b'ninja', b'check-flang'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=3896.594161

```

</details>

https://github.com/llvm/llvm-project/pull/176188