Create long-running test for catching leaks.

Create a long running (over night) test for catching memory leaks.

• MaxScale configured with a typical M/S backend and RWS.
• Clients of different character - varying session length, workload, amount of prepared statement, etc. - that continuously execute queries.

The amount of memory used should be tracked so that it at the end is possible to say whether the memory usage stays flat or is continuously increasing.