reset buffer stats in HostScoring

[SeverinDiederichs]

This PR fixes a critical bug in the HostScoring implementation:

The 3 variables required for the next hit slot

  hostScoring_dev->fBufferStart        = 0;
  *(hostScoring_dev->fNextFreeHit_dev) = 0;
  *(hostScoring_dev->fUsedSlots_dev)   = 0;

were not reset between events. Although they were ever increased via unsigned int next = hostScoring_dev->fNextFreeHit_dev->fetch_add(1); (and the fBufferStart was set to be the fNextHitFree), it worked due to the circular nature of the buffer return next % hostScoring_dev->fBufferCapacity;. However, as soon as the maximum int was exceeded, the simulation would simply stall and not do anything else anymore. This PR fixes that by resetting the three variables between events using a new function ResetBufferStatsGPU.

Note that there are a huge amount of changes due to the missing clang formatting in the file. The only other change was to reduce some input parameters for e.g., CopyHitsToHost and just use the hostscoring itself to get the stats.

[phsft-bot]

Can one of the admins verify this patch?

[agheata]

Good for me, except resetting the counters in a new kernel launch, see comment inline. I wonder why the CI doesn't catch missing clang-format, we need to investigate.