[Integrated] RFR: Improve handling of squash and rebase of PRs

[Robin Westberg]

Changeset: 15cf5f69
Author:    Robin Westberg <rwestberg at openjdk.org>
Date:      2020-04-20 06:46:50 +0000
URL:       https://git.openjdk.java.net/skara/commit/15cf5f69

Improve handling of squash and rebase of PRs

Reviewed-by: ehelin

! bots/pr/src/main/java/org/openjdk/skara/bots/pr/CheckRun.java
! bots/pr/src/main/java/org/openjdk/skara/bots/pr/IntegrateCommand.java
! bots/pr/src/main/java/org/openjdk/skara/bots/pr/PullRequestInstance.java
! bots/pr/src/main/java/org/openjdk/skara/bots/pr/SponsorCommand.java
! bots/pr/src/test/java/org/openjdk/skara/bots/pr/CheckTests.java
! bots/pr/src/test/java/org/openjdk/skara/bots/pr/MergeTests.java
! jcheck/src/test/java/org/openjdk/skara/jcheck/TestRepository.java
! vcs/src/main/java/org/openjdk/skara/vcs/ReadOnlyRepository.java
! vcs/src/main/java/org/openjdk/skara/vcs/Repository.java
+ vcs/src/main/java/org/openjdk/skara/vcs/Tree.java
! vcs/src/main/java/org/openjdk/skara/vcs/git/GitRepository.java
! vcs/src/main/java/org/openjdk/skara/vcs/hg/HgRepository.java