[Integrated] RFR: If there are no changes after squashing, fail jcheck

[Robin Westberg]

Changeset: 6ef64684
Author:    Robin Westberg <rwestberg at openjdk.org>
Date:      2019-11-25 09:56:06 +0000
URL:       https://git.openjdk.java.net/skara/commit/6ef64684

169: If there are no changes after squashing, jcheck should fail

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/IntegrateTests.java