[llvm] [AMDGPU] auto-generate file check line for amdgcn.bitcast.ll (PR #131955)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-sie-win` running on `sie-win-worker` while building `llvm` at step 7 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/46/builds/13814

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

```
Step 7 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: SemaCXX/builtin-structured-binding-size.cpp' FAILED ********************
Exit Code: 3221226356

Command Output (stdout):
--
# RUN: at line 1
z:\b\llvm-clang-x86_64-sie-win\build\bin\clang.exe -cc1 -internal-isystem Z:\b\llvm-clang-x86_64-sie-win\build\lib\clang\21\include -nostdsysteminc Z:\b\llvm-clang-x86_64-sie-win\llvm-project\clang\test\SemaCXX\builtin-structured-binding-size.cpp -std=c++2c -fsyntax-only -verify
# executed command: 'z:\b\llvm-clang-x86_64-sie-win\build\bin\clang.exe' -cc1 -internal-isystem 'Z:\b\llvm-clang-x86_64-sie-win\build\lib\clang\21\include' -nostdsysteminc 'Z:\b\llvm-clang-x86_64-sie-win\llvm-project\clang\test\SemaCXX\builtin-structured-binding-size.cpp' -std=c++2c -fsyntax-only -verify
# note: command had no output on stdout or stderr
# error: command failed with exit status: 0xc0000374

--

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


```

</details>

https://github.com/llvm/llvm-project/pull/131955