Summary:
This also adds testing of 32-bit V9 atomic lowering, splitting the
64-bit-only tests out into their own file.
Reviewers: venkatra, jyknight
Reviewed By: jyknight
Subscribers: hiraditya, fedor.sergeev, jfb, llvm-commits, glaubitz
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69352
James Clarke