Synchronize VEX JIT encoding code with the MCJIT version. Fix a bug in the MCJIT code where CurOp was being incremented even if the operand it was pointing at wasn't used. Maybe only matters if there are any EVEX_K instructions that aren't VEX_4V.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188868 91177308-0d34-0410-b5e6-96231b3b80d8