Revert XFAIL a codegen test AArch64/tailmerging_in_mbp.ll
Revert XFAIL a codegen test AArch64/tailmerging_in_mbp.ll

This reverts r373103 (git commit a524e630a793e18e7d5fabc2262781f310eb0279)

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@373116 91177308-0d34-0410-b5e6-96231b3b80d8

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