Threads may try to acquire two locks in different orders, potentially causing deadlock

Defect 105073 (STATIC_C)
Checker ORDER_REVERSAL (subcategory none)
File: /src/libmongoc/tests/mock_server/mock-server.c
Function main_thread
/src/libmongoc/tests/mock_server/mock-server.c, line: 1577
Calling "pthread_mutex_lock" acquires lock "_mock_server_t.mutex".

             bson_mutex_lock (&server->mutex);