[jdk20u] RFR: 8299194: CustomTzIDCheckDST.java may fail at future date

[Ichiroh Takiguchi]

8299194: CustomTzIDCheckDST.java may fail at future date

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Commit messages:
 - Backport 5e2de89628aaf6acb8e458fb417426ca5e477bea

Changes: https://git.openjdk.org/jdk20u/pull/3/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk20u&pr=3&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8299194
  Stats: 21 lines in 1 file changed: 16 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk20u/pull/3.diff
  Fetch: git fetch https://git.openjdk.org/jdk20u pull/3/head:pull/3

PR: https://git.openjdk.org/jdk20u/pull/3