Mark XACQUIRE_PREFIX/XRELEASE_PREFIX as isAsmParserOnly so they'll disappear from the disassembler table build without custom filtering code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201215 91177308-0d34-0410-b5e6-96231b3b80d8
Remove special case filtering for instructions with lock prefix as they are all marked with isCodeGenOnly already.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201216 91177308-0d34-0410-b5e6-96231b3b80d8