Try to address MDEV-17745

wait_all_purged.inc: Wait for 60 seconds instead of 30 seconds.
Purge can be slow on buildbot, especially in ASAN-instrumented builds.

mysql-test/suite/innodb/include/wait_all_purged.inc

@@ -7,7 +7,7 @@ if (!$wait_all_purged)
 }
 let $remaining_expect= `select concat('InnoDB		',$wait_all_purged)`;
 
-let $wait_counter= 300;
+let $wait_counter= 600;
 while ($wait_counter)
 {
     --replace_regex /.*History list length ([0-9]+).*/\1/