Attempt to fix a failure in test case innodb.innodb_information_schema seen occasionally in Buildbot.

The test case waits for other threads to complete, but the wait is only 2
seconds. This is likely to sometimes be too little on our heavily loaded
buildbot VMs, that can easily stall for more than 2 seconds from time to time.

So let's try to increase the timeout (to about 40 seconds) and see if it
helps.

mysql-test/suite/innodb/t/innodb_information_schema.test

@@ -122,7 +122,7 @@ SELECT * FROM ```t'\"_str` WHERE c1 = '4' FOR UPDATE;
 # then its contents will never change because the cache from which it is
 # filled is updated only if it has not been read for 0.1 seconds. See
 # CACHE_MIN_IDLE_TIME_US in trx/trx0i_s.c.
-let $cnt=10;
+let $cnt=200;
 while ($cnt)
 {
     let $success=`SELECT COUNT(*) = 14 FROM INFORMATION_SCHEMA.INNODB_LOCKS`;