Add restarter script to test for dvfss issues.

[hramrach]

[ssvb]

I think that it is a good idea to test problems in isolation. Which means one test for DRAM and another test for DVFS. The whole purpose of having dedicated tests is that we have a good idea about what exactly is failing, and then can fix these problems one at a time.

If the stability issue can't be detected by individual tests and needs them to be running simultaneously, then we need to investigate it and try our best to improve these tests.