[jdk23u] RFR: 8340552: Harden TzdbZoneRulesCompiler against missing zone names

[Antonio Vieiro]

Clean backport of JDK-8340552.

Tested tier1 tests and processing data from tzdata/2024b.

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Commit messages:
 - Backport 1bc13a1c10a580f84f1b7686c95344ec2633f611

Changes: https://git.openjdk.org/jdk23u/pull/230/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk23u&pr=230&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8340552
  Stats: 12 lines in 1 file changed: 8 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk23u/pull/230.diff
  Fetch: git fetch https://git.openjdk.org/jdk23u.git pull/230/head:pull/230

PR: https://git.openjdk.org/jdk23u/pull/230