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, 1 deletions

diff --git a/sql/wsrep_applier.cc b/sql/wsrep_applier.cc
index 49087d09224..db92878dbe5 100644
--- a/sql/wsrep_applier.cc
+++ b/sql/wsrep_applier.cc
@@ -224,7 +224,8 @@ wsrep_cb_status_t wsrep_apply_cb(void* const             ctx,
                  {
                    const char act[]=
                      "now "
-                     "wait_for signal.wsrep_apply_cb";
+                     "SIGNAL sync.wsrep_apply_cb_reached "
+                     "WAIT_FOR signal.wsrep_apply_cb";
                    DBUG_ASSERT(!debug_sync_set_action(thd,
                                                       STRING_WITH_LEN(act)));
                  };);