[jdk21u-dev] RFR: 8313231: Redundant if statement in ZoneInfoFile

[Daniel Hu]

Clean backport. Removes a redundant if statement. Passes GHA.

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Commit messages:
 - Backport f8c2b7fee101d66107704b3ee464737c5ccdc13a

Changes: https://git.openjdk.org/jdk21u-dev/pull/2325/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2325&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8313231
  Stats: 4 lines in 1 file changed: 0 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/2325.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/2325/head:pull/2325

PR: https://git.openjdk.org/jdk21u-dev/pull/2325