Refactored the implementation of AArch64 NEON instruction ZIP, UZP
and TRN.
Fix a bug when mixed use of vget_high_u8() and vuzp_u8().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195716 91177308-0d34-0410-b5e6-96231b3b80d8