[llvm] [DWARFLinker] Allow emission of repeated identical discriminators (PR #98255)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `arc-builder` running on `arc-worker` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/3/builds/1351

Here is the relevant piece of the build log for the reference:
```
Step 6 (test-build-unified-tree-check-all) failure: 1200 seconds without output running [b'ninja', b'check-all'], attempting to kill
0.853 [58/18/1] Linking CXX executable tools/clang/unittests/Basic/BasicTests
1.614 [57/18/2] Linking CXX executable tools/clang/unittests/Format/FormatTests
6.363 [56/18/3] Linking CXX executable tools/clang/unittests/Lex/LexTests
6.852 [55/18/4] Linking CXX executable tools/clang/unittests/libclang/libclangTests
6.982 [54/18/5] Linking CXX executable tools/clang/unittests/CrossTU/CrossTUTests
6.993 [53/18/6] Linking CXX executable tools/clang/unittests/Analysis/ClangAnalysisTests
7.025 [52/18/7] Linking CXX executable tools/clang/unittests/Tooling/Syntax/SyntaxTests
7.199 [51/18/8] Linking CXX executable tools/clang/unittests/ASTMatchers/Dynamic/DynamicASTMatchersTests
8.283 [50/18/9] Linking CXX executable tools/clang/unittests/AST/Interp/InterpTests
8.481 [49/18/10] Linking CXX executable tools/clang/unittests/InstallAPI/InstallAPITests
command timed out: 1200 seconds without output running [b'ninja', b'check-all'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1209.169008

```

https://github.com/llvm/llvm-project/pull/98255