x86: skip hyperv_clock test when host clocksource is not TSC

Hyper-V TSC page clocksource is TSC based so it requires host to use TSC
for clocksource. While TSC is more or less standard for x86 hardware
nowadays, when kvm-unit-tests are run in a VM the clocksource tends to be
different (e.g. kvm-clock).

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200617152139.402827-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>