KVM: selftests: Use TAP interface in the kvm_binary_stats_test

The kvm_binary_stats_test test currently does not have any output (unless
one of the TEST_ASSERT statement fails), so it's hard to say for a user
how far it did proceed already. Thus let's make this a little bit more
user-friendly and include some TAP output via the kselftest.h interface.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Message-Id: <20221004093131.40392-2-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>