kvm-unit-tests: nSVM: Test that DR6[63:32], DR7[63:32] and EFER reserved bits...

kvm-unit-tests: nSVM: Test that DR6[63:32], DR7[63:32] and EFER reserved bits are not set on vmrun of nested guests

According to section "Canonicalization and Consistency Checks" in APM vol. 2
the following guest state is illegal:

    "DR6[63:32] are not zero."
    "DR7[63:32] are not zero."
    "Any MBZ bit of EFER is set."

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Message-Id: <20200522221954.32131-4-krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>