x86: Test single stepping with emulated instructions

This test checks that single stepping through CPUID and RDMSR works.
Both instructions trigger VM exits and are emulated by the hypervisor.

Signed-off-by: Kyle Huey <khuey@kylehuey.com>
[Fixed dr6 indices to check even dr6[5] and dr6[6].]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>