1) ptimer-test is not a qtest---it runs the ptimer.c code directly in the
ptimer-test process

2) ptimer-test has its own stubs file, so there is no need to add more
stubs to stubs/vmstate.c
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>