[clang-tidy] Fix findNextTokenSkippingComments & rangeContainsExpansionsOrDirectives

findNextTokenSkippingComments is actually a endless loop,
implementing it correctly.
rangeContainsExpansionsOrDirectives were skiping every second
token, if there were no whitespaces bettwen tokens.

Reviewed By: carlosgalvezp

Differential Revision: https://reviews.llvm.org/D146881