PT-2160 fix tests for pt online schema change (#602)

* PT-2160 - Fix tests for pt-online-schema-change

Re-enabled tests after MySQL bug #89441 fix in 8.0.14 and later
Updated t/pt-online-schema-change/samples/basic_no_fks_innodb.sql, so its unique index is NOT NULL
Added synchonizations when tests are waiting for too long due to slave catch up
Added innodb_directories option for t/pt-online-schema-change/pt-244.t

* PT-2160 - Fix tests for pt-online-schema-change
PT-2048 - pt-osc spans excessive connections to the replica when executing in the source

t/pt-online-schema-change/slave_lag.t was failing due to PT-2048. I added code that reuses already created connections when checks for slave in the wait loop. It fixes slave_lag.t too.
I also added that prints more detailed error when fails to connect to the replica.

* PT-2160 - Fix tests for pt-online-schema-change

Modified t/pt-online-schema-change/slave_lag.t, so it runs and clean ups faster.

* PT-2160 - Fix tests for pt-online-schema-change

Modified t/pt-online-schema-change/pt-1455.t, so it runs and clean ups faster.

* PT-2160 - Fix tests for pt-online-schema-change

Fixed search for HASH and BTREE keys broken by fix for PT-2123
Updated modules for pt-archiver
Fixed die message for sandbox/start-sandbox
Added global_grants table to list of exceptions for the ok function in lib/Sandbox.pm
Added wait_for_slaves to bugs.t, so changes on the source are copied to replica before pt-osc starts working
Updated PXC tests
Added wait_for_slaves to pt-1455.t
Fixed regular expression in pt-229.t, so it works with both 5.x and 8.0 versions
Added innodb_directories option for pt-244.t, so it does not fail on 8.0
Modified slave_lag.t, so it is more stable and slow enough, so pt-osc can print message about delayed replicas

t/pt-online-schema-change/issue-1646713.t

@@ -26,10 +26,6 @@ require "$trunk/bin/pt-online-schema-change";
 my $dp = new DSNParser(opts=>$dsn_opts);
 my $sb = new Sandbox(basedir => '/tmp', DSNParser => $dp);
 
-if ($sandbox_version ge '8.0') {
-    plan skip_all => 'PXC 8 does not exist yet';
-}
-
 our ($master_dbh, $master_dsn) = $sb->start_sandbox(
    server => 'master',
    type   => 'master',