minimatch: reset match field index for each bitmap word
minimatch: reset match field index for each bitmap word

When we finish with a bitmap word (bitmap_word == 0) we don't increment the
match field index by the number of bits remaining in the bitmap word, since
__builtin_ctz can't give us this information. We need to skip to the first
match field index of the new bitmap word.

minimatch_overlap didn't actually need this variable.

harfly/indigo,harfly/indigo,harfly/indigo,harfly/indigo