Revert "[X86][InlineAsm][Ms Compatibility]Prefer variable name over a register when the two collides"

This reverts r308867 and r308866.

It broke the sanitizer-windows buildbot on C++ code similar to the
following:

  namespace cl { }
  void f() {
    __asm {
      mov al, cl
    }
  }

t.cpp(4,13):  error: unexpected namespace name 'cl': expected expression
    mov al, cl
            ^

In this case, MSVC parses 'cl' as a register, not a namespace.

llvm-svn: 308926
GitOrigin-RevId: c990b5d9165c3bf12240b94a666944bcaaea0970