[FEATURE] Shrink getprime runs for OSTest

### Is your feature request related to a problem? Please describe.

OSTest is a huge pain in the ass to run on small targets with the getprime test enabled because it takes so long to complete that step.

### Describe the solution you'd like

I don't think we need 10 runs of getprime in the test; maybe just 3 is fine?

### Describe alternatives you've considered

Make the number of getprime runs configurable so it can be fewer on small targets.

### Verification

- [x] I have verified before submitting the report.

Start by searching the OSTest code for the getprime test and its run count; no file path is given in the issue. Run OSTest on a small target and verify that getprime completes with three runs, or a configurable lower count, while the test still passes.

Written by the indexing model from the issue text.