repeat/atleast applied to goto/gopast on (non-)grouping #286

I added an optimisation for this case in v3.0.0: 5ef33ae

However, the repeat_score() change there is was flawed as it requires that the code in the loop preserves the cursor's value on failure, but the target language helper functions used here don't currently do that. I have turned this optimisation off for v3.1.0: 3021622

The helpers could probably preserve the cursor on failure fairly easily and without significant overhead, so we should investigate doing that and reinstating the optimisation.