sync_close destroys priority mutexes as regular ones
|Percona Server||Status tracked in 5.6|
Split off bug 1291202:
If sync_close encounters any priority mutexes on mutex_list, they are freed using the wrong overload. It is relatively benign, it only results in leaked high priority event and skipped high waiters flag equal to zero assertion.
The mutexes in question are buffer pool LRU and free list mutexes.