[SYCL] Prohibit arithmetic operations for incompatible pointers

Summary:
This change enables OpenCL diagnostics for the pointers annotated with
address space attribute SYCL mode.

Move `isAddressSpaceOverlapping` method from PointerType to QualType.

Reviewers: Anastasia, rjmccall

Reviewed By: rjmccall

Subscribers: rjmccall, jeroen.dobbelaere, Fznamznon, yaxunl, ebevhan, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80317