ZTS: Wait on all events in events_001_pos.ksh

The events_001_pos.ksh test case can fail because it's possible,
and correct, for the config_sync event to be posted after the last
"expected" event. To accommodate this the run_and_verify() function
has been updated to wait for all non-history events, not just the
last event. This does not increase the run time of the test as
long as all the events do get generated.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #11147