[X86] Add test case that led to the revert of r363802, r363850, and r363856 in r364264
[X86] Add test case that led to the revert of r363802, r363850, and r363856 in r364264

I've been trying to fix this, but hit some roadblocks. So I'm
committing the test case for now so we'll at least avoid
recreating that failure.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@364272 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm