tests: wait for migration completion before looking for STOP event

When moving into the convergance phase, the precopy tests will first
look for a STOP event and once found will look for migration completion
status. If the test VM is not converging, the test suite will be waiting
for the STOP event forever. If we wait for the migration completion
status first, then we will trigger the previously added timeout and
prevent the test hanging forever.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20220628105434.295905-3-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/qtest/migration-test.c

@@ -1232,6 +1232,10 @@ static void test_precopy_common(MigrateCommon *args)
 
         migrate_set_parameter_int(from, "downtime-limit", CONVERGE_DOWNTIME);
 
+        /* We do this first, as it has a timeout to stop us
+         * hanging forever if migration didn't converge */
+        wait_for_migration_complete(from);
+
         if (!got_stop) {
             qtest_qmp_eventwait(from, "STOP");
         }
@@ -1239,7 +1243,6 @@ static void test_precopy_common(MigrateCommon *args)
         qtest_qmp_eventwait(to, "RESUME");
 
         wait_for_serial("dest_serial");
-        wait_for_migration_complete(from);
     }
 
     if (args->finish_hook) {