[x86] Remove redundant call to setTargetDAGCombine for BUILD_VECTOR node type.
[x86] Remove redundant call to setTargetDAGCombine for BUILD_VECTOR node type.

Since revision 235394, we no longer perform target specific combines on
build_vector nodes. No functional change intended.


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@265138 91177308-0d34-0410-b5e6-96231b3b80d8

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