First round of fixes for the x86 fixes for the x86 move accumulator from/to memory...

First round of fixes for the x86 fixes for the x86 move accumulator from/to memory offset instructions.

-Assembly parser now properly check the size of the memory operation specified in intel syntax. So 'mov word ptr [5], al' is no longer accepted.
-x86-32 disassembly of these instructions no longer sign extends the 32-bit address immediate based on size.
-Intel syntax printing prints the ptr size and places brackets around the address immediate.

Known remaining issues with these instructions:
-Segment override prefix is not supported. PR16962 and PR16961.
-Immediate size should be changed by address size prefix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189201 91177308-0d34-0410-b5e6-96231b3b80d8