[clang] [clang-tools-extra] [clang-tidy] Avoid matching nodes in system headers (PR #151035)

[Carlos Galvez via cfe-commits]

carlosgalvezp wrote:

@Xazax-hun @steakhal @AaronBallman Do you have any feedback on the changes to `ASTMatchers`?

https://github.com/llvm/llvm-project/pull/151035