Summary
We've seen pipeline creation from a totally empty repository regress more than once:
https://issues.jenkins-ci.org/browse/JENKINS-46723
https://issues.jenkins-ci.org/browse/JENKINS-50572
Our GitHub tests cover this pretty well already, so this ticket is to track the creation of empty-repo tests against Bitbucket repos.

Acceptance criteria:
Create an end to end test for Bitbucket server, which goes all the way to the end of the usual create flow. It appears that this test stops short of actually committing the change to the repository, and that's where we're having these regressions.