GlobalReplace with patterns ending in .*$ scans entire input through BitState unnecessarily

[cosu]

When using RE2::GlobalReplace with patterns ending in .*$ (or .*) where the .* contributes no capture groups, BitState scans the entire input string to track the .* states, even though it is guaranteed to consume the rest of the string.

This is a pretty common usecase for log processing where a regex like ^https?://(?:www\.)?([^/]+)/.*$ is used to extract hostnames from web logs.

It should be possible to short-circuit the match once everything before the trailing .* has been matched, avoiding the cost of scanning the remainder of the input.

I prototyped this by stripping the trailing.*$ and using RE2::Extract instead of GlobalReplace, which significantly reduced BitState CPU. However, I had to add a guard to fall back when the replacement references \0 (full match), since the matched portion changes.

Is this approach sound? Are there other edge cases or correctness issues I might be missing? Would this be worth handling natively in RE2?