[clang] [CIR][CUDA]: Handle duplicate mangled names (PR #183976)

[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 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/157/builds/44971

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

```
Step 5 (build-unified-tree) failure: build (failure) (timed out)
...
69.031 [6693/31/671] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/OnDiskGraphDB.cpp.o
69.033 [6693/30/672] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/OnDiskKeyValueDB.cpp.o
69.034 [6693/29/673] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/OnDiskCommon.cpp.o
69.036 [6693/28/674] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/OnDiskTrieRawHashMap.cpp.o
69.038 [6693/27/675] Building CXX object lib/CAS/CMakeFiles/LLVMCAS.dir/UnifiedOnDiskCache.cpp.o
69.039 [6693/26/676] Building CXX object lib/Telemetry/CMakeFiles/LLVMTelemetry.dir/Telemetry.cpp.o
69.041 [6693/25/677] Building CXX object lib/WindowsManifest/CMakeFiles/LLVMWindowsManifest.dir/WindowsManifestMerger.cpp.o
69.043 [6693/24/678] Building CXX object utils/UnicodeData/CMakeFiles/UnicodeNameMappingGenerator.dir/UnicodeNameMappingGenerator.cpp.o
69.045 [6693/23/679] Building CXX object tools/llvm-undname/CMakeFiles/llvm-undname.dir/llvm-undname.cpp.o
69.047 [6693/22/680] Building CXX object tools/reduce-chunk-list/CMakeFiles/reduce-chunk-list.dir/reduce-chunk-list.cpp.o
command timed out: 1200 seconds without output running [b'ninja'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1270.119679

```

</details>

https://github.com/llvm/llvm-project/pull/183976