[clang-tidy] Partly rewrite readability-simplify-boolean-expr using RAV

[clang-tidy] Partly rewrite readability-simplify-boolean-expr using RAV

The check was using AST matchers in a very inefficient manner. By rewriting the
BinaryOperator-related parts using RAV, the check was sped up by a factor of
up to 10000 on some files (mostly, generated code using binary operators in
tables), but also significantly sped up for regular large files.
As a side effect, the code became clearer and more readable.

llvm-svn: 303081