RFR: 8254982: (tz) Upgrade time-zone data to tzdata2020c

[Kiran Sidhartha Ravikumar]

Hi Guys,

Please review the integration of tzdata2020c to JDK.

Details regarding the change can be viewed at - https://mm.icann.org/pipermail/tz-announce/2020-October/000060.html
Bug: https://bugs.openjdk.java.net/browse/JDK-8254982

Along with it, there is a test fix for https://bugs.openjdk.java.net/browse/JDK-8254865, With tzdata2020b, the test
fails for the mentioned zones expecting "PST" but JDK has Zone names for "MST" for JRE locale provider. Since the
purpose of the test is to get any GMT-08:00 time zone, I have excluded those zones from the test.

Please let me know if the changes are good to push.

Thanks,
Kiran

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Commit messages:
 - 8254982: (tz) Upgrade time-zone data to tzdata2020c

Changes: https://git.openjdk.java.net/jdk/pull/747/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=747&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8254982
  Stats: 30 lines in 4 files changed: 27 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/747.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/747/head:pull/747

PR: https://git.openjdk.java.net/jdk/pull/747