[clang] [clang] [unittest] Add a test for Generic_GCC::GCCVersion::Parse (PR #69078)

[Timm Baeder via cfe-commits]

tbaederr wrote:

FWIW this failed for me locally as well but I'm not using `BUILD_SHARED_LIBS`. I am linking with the clang dylib though, which has the same problem I think.

https://github.com/llvm/llvm-project/pull/69078