t1027: add flux job wait-event

Problem: When running t1027-mf-priority-issue376.t under valgrind, the
test that checks for contents of the eventlog fails because the test
does not wait for the job to reach the desired job state before checking
the eventlog.

Add "flux job wait-event" to the test so that the test waits for the job
to reach the desired job state before looking for certain events in the
eventlog.

t/t1027-mf-priority-issue376.t

@@ -54,6 +54,7 @@ test_expect_success 'submit job for testing' '
 
 test_expect_success 'update of duration of pending job works while at active jobs limit' '
 	flux update $jobid1 duration=1m &&
+	flux job wait-event -vt 10 $jobid1 priority &&
 	flux job eventlog $jobid1 \
 		| grep jobspec-update \
 		| grep duration=60