AMDGPU: Make isIntrinsicSourceOfDivergence table-driven

Summary:
This is in preparation for the new dimension-aware image intrinsics,
which I'd rather not have to list here by hand.

Change-Id: Iaa16e3a635a11283918ce0d9e1e618591b0bf6fa

Reviewers: arsenm, rampitec, b-sumner

Subscribers: kzhuravl, wdng, yaxunl, dstuttard, tpr, llvm-commits, t-tye

Differential Revision: https://reviews.llvm.org/D44938

llvm-svn: 328939