mysqltest was reading free-ed memory, which fooled the test's reconnection detection.

client/mysqltest.cc:
  Fix for BUG#43001 ""maria.maria-no-logging fails sporadically on valgrind in PS mode"
  mysqltest was closing (=>free()ing) the "stmt" object before reading stmt->last_errno
  (and storing that into $mysql_errno). As wait_until_connected_again.inc tests the value
  of $mysql_errno to know if reconnection has been accomplished, it was fooled.