[mlir][interfaces] Add insideMutuallyExclusiveRegions helper

Add a helper function to ControlFlowInterfaces for checking if two ops
are in mutually exclusive regions according to RegionBranchOpInterface.

Utilize this new helper in Linalg ComprehensiveBufferize. This makes the
analysis independent of the SCF dialect and generalizes it to other ops
that implement RegionBranchOpInterface.

Differential Revision: https://reviews.llvm.org/D114220