GitLab is used only for code review, issue tracking and project management. Canonical locations for source code are still https://gitweb.torproject.org/ https://git.torproject.org/ and git-rw.torproject.org.
One of #2355 (moved)'s patches implies that you can reuse old circuits after you setconf a bridge. I just confirmed it on my Tor client.
(This is #1090 (moved) related too.)