Unnecessary loop

https://github.com/dropbox/rust-brotli/blob/5d82b69d1aaee6e0fdac6a35654cf7cea40c1057/src/enc/backward_references/hq.rs#L920

This loop `continue30` is unnecessary because it will eventually break at line 1018. If we remove this loop and change all the `break 'continue30;` into `continue` and change all the `break 'break29;` into `break`, the execution time will decreased from 3.76s to 3.43s based on my test, which is a 1.1x speedup.

Hope this information helps!

Start in src/enc/backward_references/hq.rs around line 920 and inspect the continue30 loop through the break near line 1018. Reproduce the reported execution-time comparison, then verify that the requested loop and label changes preserve behavior while achieving the reported performance improvement.

Written by the indexing model from the issue text.