[clang] [Clang] Deprecate `__is_trivially_relocatable` (PR #138835)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-sie-ubuntu-fast` running on `sie-linux-worker` while building `clang` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/144/builds/24541

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: SemaCXX/attr-trivial-abi.cpp' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/lib/clang/21/include -nostdsysteminc -fsyntax-only -verify /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/SemaCXX/attr-trivial-abi.cpp -std=c++11 # RUN: at line 1
+ /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/lib/clang/21/include -nostdsysteminc -fsyntax-only -verify /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/SemaCXX/attr-trivial-abi.cpp -std=c++11
error: 'expected-error' diagnostics seen but not expected: 
  File /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/SemaCXX/attr-trivial-abi.cpp Line 57: static assertion failed due to requirement '__builtin_is_cpp_trivially_relocatable(S3_3)': 
  File /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/SemaCXX/attr-trivial-abi.cpp Line 159: static assertion failed due to requirement '__builtin_is_cpp_trivially_relocatable(deletedCopyMoveConstructor::CopyMoveDeleted)': 
  File /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/SemaCXX/attr-trivial-abi.cpp Line 172: static assertion failed due to requirement '__builtin_is_cpp_trivially_relocatable(deletedCopyMoveConstructor::S18)': 
  File /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/SemaCXX/attr-trivial-abi.cpp Line 203: static assertion failed due to requirement '__builtin_is_cpp_trivially_relocatable(deletedCopyMoveConstructor::S19)': 
  File /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/SemaCXX/attr-trivial-abi.cpp Line 204: static assertion failed due to requirement '!__is_trivially_relocatable(deletedCopyMoveConstructor::S19)': 
5 errors generated.

--

********************


```

</details>

https://github.com/llvm/llvm-project/pull/138835