[X86][SSE] Move combineTo call out of combineX86ShuffleChain. NFCI.
[X86][SSE] Move combineTo call out of combineX86ShuffleChain. NFCI.

First step towards making it possible to use the shuffle combines for cases where we don't want to call DCI.CombineTo() with the result.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@312884 91177308-0d34-0410-b5e6-96231b3b80d8

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