selftests: kvm: test enforcement of paravirtual cpuid features

Add a set of tests that ensure the guest cannot access paravirtual msrs
and hypercalls that have been disabled in the KVM_CPUID_FEATURES leaf.
Expect a #GP in the case of msr accesses and -KVM_ENOSYS from
hypercalls.

Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Aaron Lewis <aaronlewis@google.com>
Message-Id: <20201027231044.655110-7-oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>