RFR: 6961: Fix rules test

[Marcus Hirt]

Setting a fixed timezone so that the tests don't fail locally. Strange that this happened all of a sudden though.

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Commit messages:
 - Forcing time-zone to GMT
 - 6961: Fix rules baseline

Changes: https://git.openjdk.java.net/jmc/pull/151/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=151&range=00
  Issue: https://bugs.openjdk.java.net/browse/JMC-6961
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jmc/pull/151.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/151/head:pull/151

PR: https://git.openjdk.java.net/jmc/pull/151