[clang-tidy] Use compiled regex for AllowedRegexp in macro usage check

Current check compiles the regex on every attempt at matching. The check also populates and enables a regex value by default so the default behaviour results in regex re-compilation for every macro - if the check is enabled. If people used this check there's a reasonable chance they would have relatively complex regexes in use.

This is a quick and simple fix to store and use the compiled regex.

Reviewed By: njames93

Differential Revision: https://reviews.llvm.org/D91908