[clang-tidy] Fix unit test readability/identifier-naming-anon-record-fields.cpp

[carlosgalvezp]

After making clang-tidy skip processing system headers by default, the following test case no longer works:

https://github.com/llvm/llvm-project/blob/main/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming-anon-record-fields.cpp#L36

This is because the CXXRecordDecl corresponding to the global anonymous union is not picked up by the ASTConsumer::handleTopLevelDecl function, i.e. it is not considered a top-level declaration. Most likely because it's anonymous i.e. it does not have a name. Due to this, the AST traversal does not find it and so the check cannot process this case.

[llvmbot]

@llvm/issue-subscribers-clang-tidy

Author: Carlos Galvez (carlosgalvezp)

After [making clang-tidy skip processing system headers by default](https://github.com//pull/128150), the following test case no longer works:

https://github.com/llvm/llvm-project/blob/main/clang-tools-extra/test/clang-tidy/checkers/readability/identifier-naming-anon-record-fields.cpp#L36

This is because the CXXRecordDecl corresponding to the global anonymous union is not picked up by the ASTConsumer::handleTopLevelDecl function, i.e. it is not considered a top-level declaration. Most likely because it's anonymous i.e. it does not have a name. Due to this, the AST traversal does not find it and so the check cannot process this case.

[carlosgalvezp]

Fixed by #132743