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

[Baranov Victor via cfe-commits]

vbvictor wrote:

> As a benchmark, I ran clang-tidy with all checks activated, on a single .cpp file which #includes all the standard C++ headers, then measure the time as well as found warnings.

Could you please save this file (or make a gist) for later. I think we could have some benchmarks of `clang-tidy` and this file will a bench-test.

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