[X86] Remove the AsmName from the HAX,HDX,HCX,HBX,HSI,HDI,HBP,HSP,HIP...

[X86] Remove the AsmName from the HAX,HDX,HCX,HBX,HSI,HDI,HBP,HSP,HIP artificial registers so they can't be parsed by the assembly parser.

There are no instructions that use them so they weren't causing any bad matches. But they weren't being diagnosed as "invalid register name" if they were used and would instead trigger some form of invalid operand.

llvm-svn: 336054