[OPENMP][C++20]Add support for CXXRewrittenBinaryOperator in ranged for loops.

Added support for CXXRewrittenBinaryOperator as a condition in ranged
for loops. This is a new kind of expression, need to extend support for
  C++20 constructs.
It fixes PR49970: range-based for compilation fails for libstdc++ vector
with -std=c++20.

Differential Revision: https://reviews.llvm.org/D104240