The previous way to test hungarian notation doesn't check CHECK-FIXES.
This will allow readability-identifier-naming tests of Hungarian
notation to keep the use of an external .clang-tidy file (not embedded
within the .cpp test file) and properly check CHECK-FIXES.
Also, it turns out the hungarian notation tests use the wrong
.clang-tidy file, so fix that too to make these tests ok.
This is a part of a fix for issue https://github.com/llvm/llvm-project/issues/60670.