Speed up executing of VPE tests

Now we have ~800 JUnit tests. It takes ~20 min to execute all of them, which is too much.
The ideas how to speed them up:

1. Split them up in ratio 80%/20% where 80% - the least probable tests to fall and 20% - the most. Then execute mainly the 20% part while developing.
2. Try to optimize tests using profiler.
3. Run in parallel?