RFR: 8342886: Update MET timezone in TimeZoneNames files

[Gautham Krishnan]

MET timezone entry in TimeZoneNames.java and TimeZoneNames_*.java needs to be updated as MET is alias to Europe/Brussels as per 2024b tzdata changes.

Also Bug4848242.java needs to be removed as the test expects all euro locale time zones should have the same short names.

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Commit messages:
 - Update MET timezone in TimeZoneNames files

Changes: https://git.openjdk.org/jdk/pull/24871/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24871&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8342886
  Stats: 112 lines in 12 files changed: 0 ins; 90 del; 22 mod
  Patch: https://git.openjdk.org/jdk/pull/24871.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24871/head:pull/24871

PR: https://git.openjdk.org/jdk/pull/24871