[OpenMP,MLIR] Translation of parallel operation: num_threads, if clauses 3/n

This simple patch translates the num_threads and if clauses of the parallel
operation. Also includes test cases.
A minor change was made to parsing of the if clause to parse AnyType and
return the parsed type. Updates to test cases also.

Reviewed by: SouraVX
Differential Revision: https://reviews.llvm.org/D84798