Fix test failure on test MW-86 and remove MW-360 test.

Merged from mysql-wsrep-bugs following:

GCF-1058 MTR test galera.MW-86 fails on repeated runs
Wait for the sync point sync.wsrep_apply_cb to be reached before
executing the test and clearing the debug flag sync.wsrep_apply_cb.

The race scenario:

Intended behavior:
node2: set sync.wsrep_apply_cb in order to start waiting in the background INSERT
node1: INSERT start
node2 (background): INSERT start
node1: INSERT end
node2: send signal to background INSERT: "stop waiting and continue executing"
node2: clear sync.wsrep_apply_cb as no longer needed
node2 (background): consume the signal
node2 (background): INSERT end
node2: DROP TABLE
node2: check no pending signals are left - ok

What happens occasionally (unexpected):
node2: set sync.wsrep_apply_cb in order to start waiting in the background INSERT
node1: INSERT start
node2 (background): INSERT start
node1: INSERT end
// The background INSERT still has _not_ reached the place where it starts
// waiting for the signal:
// DBUG_EXECUTE_IF("sync.wsrep_apply_cb", "now wait_for...");
node2: send signal to background INSERT: "stop waiting and continue executing"
node2: clear sync.wsrep_apply_cb as no longer needed
// The background INSERT reaches DBUG_EXECUTE_IF("sync.wsrep_apply_cb", ...)
// but sync.wsrep_apply_cb has already been cleared and the "wait" code is not
// executed. The signal remains unconsumed.
node2 (background): INSERT end
node2: DROP TABLE
node2: check no pending signals are left - failure, signal.wsrep_apply_cb is
pending (not consumed)

Remove MW-360 test case as it is not intended for MariaDB (uses
MySQL GTID).

1 files changed, 2 insertions, 2 deletions

diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index c487835c84e..e561aa521e2 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -2756,6 +2756,7 @@ mysql_execute_command(THD *thd)
 #endif
   case SQLCOM_SHOW_STATUS:
   {
+    WSREP_SYNC_WAIT(thd, WSREP_SYNC_WAIT_BEFORE_SHOW);
     execute_show_status(thd, all_tables);
     break;
   }
@@ -5808,11 +5809,10 @@ static bool execute_show_status(THD *thd, TABLE_LIST *all_tables)
   bool res;
   system_status_var old_status_var= thd->status_var;
   thd->initial_status_var= &old_status_var;
-  WSREP_SYNC_WAIT(thd, WSREP_SYNC_WAIT_BEFORE_SHOW);
   if (!(res= check_table_access(thd, SELECT_ACL, all_tables, FALSE,
                                 UINT_MAX, FALSE)))
     res= execute_sqlcom_select(thd, all_tables);
-error:
+
   /* Don't log SHOW STATUS commands to slow query log */
   thd->server_status&= ~(SERVER_QUERY_NO_INDEX_USED |
                          SERVER_QUERY_NO_GOOD_INDEX_USED);