[clang-tidy] Optimize performance of RenamerClangTidyCheck

Refactor RenamerClangTidyCheck to achieve better performance
by removing object copies, duplicated function calls and by
using RecursiveASTVisitor.

Measured -72% execution time on bugprone-reserved-identifier.

Reviewed By: njames93

Differential Revision: https://reviews.llvm.org/D149723