[Reassociate] add baseline tests for binop swapping; NFC
[Reassociate] add baseline tests for binop swapping; NFC

Similar to rL330086, I don't know if we want to do these 
transforms here, but we might as well have the tests
here either way to show that this pass is missing 
potential functionality (intentionally or not).


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@330368 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm