Speed up TezRecovery tests

Currently, approximately 50% of the tests cases are chosen to run as there are many failure points chosen to test recovery on.

This can lead to the introduction of bugs into the code as not all test cases are run for every Tez QA run.

In addition, this can be a real development bottleneck as tests take around 20 minutes per cycle if all tests are run (10 minutes if 50% of the tests are run as usual)