ARM: Fix STREX/LDREX reecoding

The decoded MCInst wasn't reencoded as the same instruction

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183729 91177308-0d34-0410-b5e6-96231b3b80d8
ARM: Enforce decoding rules for VLDn instructions

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183731 91177308-0d34-0410-b5e6-96231b3b80d8