[clang][dataflow] Implement functionality to compare if two boolean values are equivalent.

`equivalentBoolValues` compares equivalence between two booleans. The current implementation does not consider constraints imposed by flow conditions on the booleans and its subvalues.

Depends On D128520

Reviewed By: gribozavr2, xazax.hun

Differential Revision: https://reviews.llvm.org/D128521