[X86] Remove assert in X86MCCodeEmitter.cpp that was added in r320830.

It seems to be failing real code which is concerning, but we were silently getting away with it. I'll investigate further.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320850 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed