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

[Robin Westberg]

Hi all,

Please review this change that ensures that if the contents of a PR are identical to the base after squashing, jcheck will fail (as there's nothing to integrate). Previously, this caused an exception.

Best regards,
Robin

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Commits:
 - afb5d7b6: If there are no changes after squashing, fail jcheck

Changes: https://git.openjdk.java.net/skara/pull/263/files
 Webrev: https://webrevs.openjdk.java.net/skara/263/webrev.00
  Stats: 71 lines in 5 files changed: 51 ins; 4 del; 16 mod
  Patch: https://git.openjdk.java.net/skara/pull/263.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/263/head:pull/263

PR: https://git.openjdk.java.net/skara/pull/263