testsuite: when testing against evemu files, also skip them if they are marked

If the database contains an item marked as skipped, we should not try
to check the evemu outputs.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
compare_evemu: ignore blank bit fields

What matters is when the bits are set.
Some new evemu versions may or may not show all the bits,
so skip the blank ones.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>