[GlobalISel] Add Predicates to GICombineRule

Small QoL change to allow Predicates to be used in GICombineRule.
Currently only one combine in the AMDGPU backend makes use of it.

The implementation is pretty simple to get started but of course we can expand this later on and optimize predicate checking better if needed.

Reviewed By: dsanders

Differential Revision: https://reviews.llvm.org/D136681