WIP: Potential race condition when updating PC hits

[anishnaik]

Currently, we do not use any atomic read/writes when updating the number of hits for a given PC. It is possible that this is an issue if two workers try to update the number of hits at the same time.

I do not think it is a problem because the updateCoveredAt function is executed on memory that is controlled per-worker. However, it is beneficial to investigate this further.