fix(core): fix git url regex matching taking too long

[Panaetius]

The gitlab_re that we build has an issue with catastropic backtracking.

essentially, we matched a path like /~something/owner/repo and the part that matches ~something, the part that matches owner and the part that matches repo were greedy matches for a variable number of path fragments separated by / so there's a ton of valid match combinations which regex searches exhaustively.

with this change, it only matches a single part with ~ in front, owner matches a variable path like a/b/c/d and repo only matches the last part. so the only variable-length thing is owner (in the case of subgroups in gitlab). This makes it run fast again.

I also added a test case that, with the old regex, takes 14 seconds and the duration check fails, with the new regex takes 2.3 seconds (for 14 tests) and passes.

[olevski]

Awesome that we have a test for this now!