[OpenMP][FIX] Use name + type checks not only name checks for calls

A call that is analyzed in an optimization needs to be verified against
the name and type of the runtime function to avoid that we look at
arguments that do not exist (anymore). This can happen if the signature
was rewritten. Since we will not set RFI.Declaration if the type doesn't
match we can use it (if it's not null) to determine if the signature is
as expected.

Differential Revision: https://reviews.llvm.org/D106341