RFR: 1465: Using altfixversions prevents commit comments

Mon Jun 6 10:00:59 UTC 2022

The altfixversions feature introduced in [SKARA-1213](https://bugs.openjdk.java.net/browse/SKARA-1213) had the unfortunate side effect of also blocking additional commit comments from being added to existing backports. I think this needs to be fixed as those additional commit comments help integrators track where and when changes move between different repos.

This patch fixes this and adjusts the relevant test.

-------------

Commit messages:
 - SKARA-1465

Changes: https://git.openjdk.java.net/skara/pull/1330/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1330&range=00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-1465
  Stats: 9 lines in 2 files changed: 7 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/skara/pull/1330.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1330/head:pull/1330

PR: https://git.openjdk.java.net/skara/pull/1330