Fix for fuzzer timeout: https://oss-fuzz.com/testcase-detail/5001604901240832.
- Operation limit is per glyph, so 100,000 should still be far more than needed.
- Switches from for(...) to while(...) loop for iteration. for(...) calls it.end() which in this case triggers a complete iteration.
- Cache CompositeGlyph size in the iterator to avoid needing to recalculate it.
Garret Rieger