testsuite: fix potential races in t4011-match-duration.t

Problem: There are two potential race conditions in the final test in
t4011-match-duration.t which ensures the internal expiration of the
scheduler resource is adjusted after an expiration update.

 1. A check for the default duration of a submitted job assumes the
   duration will be strictly less than the instance duration, but if
   the job starts within the same second as the instance starttime
   then the duration could match exactly the instance duration since
   Fluxion deals in whole seconds.

 2. The scheduler is notified of the expiration update asynchronously
   with respect to the instance update, which is detected in the test
   via the resource-update event in the resource.eventlog. This could
   result in the second submitted job receiving an unexpected default
   duration.

Fix case 1 above by allowing the job duration to match (but not
exceed) the instance duration. Fix case 2 by blocking the test until
the scheduler emits a log message for the duration update.

Author: grondo

t/t4011-match-duration.t

@@ -12,6 +12,8 @@ test_under_flux 2
 flux setattr log-stderr-level 1
 export FLUX_URI_RESOLVE_LOCAL=t
 
+dmesg_grep="flux python ${SHARNESS_TEST_SRCDIR}/scripts/dmesg-grep.py"
+
 # Ensure fluxion modules are loaded under flux-alloc(1)
 test_expect_success 'set FLUX_RC_EXTRA so Fluxion modules are loaded under flux-alloc' '
 	mkdir rc1.d &&
@@ -102,7 +104,7 @@ test_expect_success FLUX_UPDATE_RUNNING \
 	id1=$(flux proxy $id flux submit sleep 300) &&
 	duration1=$(subinstance_get_job_duration $id $id1) &&
 	test_debug "echo initial duration of subinstance job1 is $duration1" &&
-	echo $duration1 | jq -e ". < 300" &&
+	echo $duration1 | jq -e ". <= 300" &&
 	test_debug "echo updating duration of alloc job +5m" &&
 	flux update $id duration=+5m &&
 	test_debug "echo waiting for resource-update event" &&
@@ -111,6 +113,8 @@ test_expect_success FLUX_UPDATE_RUNNING \
 	exp2=$(subinstance_get_expiration $id) &&
 	test_debug "echo expiration updated from $exp1 to $exp2" &&
 	echo $exp2 | jq -e ". == $exp1 + 300" &&
+	flux proxy $id $dmesg_grep -vt 30 \
+		\"sched.*resource expiration updated\" &&
 	id2=$(flux proxy $id flux submit sleep 300) &&
 	duration2=$(subinstance_get_job_duration $id $id2) &&
 	test_debug "echo duration of subinstance job2 is $duration2" &&