[clang] [clang][driver] Fix an issue where clang does not correctly resolve the system header if invoked via symlink (on MacOS) (PR #68091)

[Liviu Ionescu via cfe-commits]

ilg-ul wrote:

@jansvoboda11, as Martin showed before, Apple clang did not fix this, so this patch applies to it too.

https://github.com/llvm/llvm-project/pull/68091