[jdk8u-dev] RFR: 8340552: Harden TzdbZoneRulesCompiler against missing zone names

[Dmitry Cherepanov]

The changes are the same as submitted by https://github.com/openjdk/jdk8u/pull/66 but now moved to https://github.com/openjdk/jdk8u-dev

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Commit messages:
 - Backport 1bc13a1c10a580f84f1b7686c95344ec2633f611

Changes: https://git.openjdk.org/jdk8u-dev/pull/623/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=623&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/jdk8u-dev/pull/623.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/623/head:pull/623

PR: https://git.openjdk.org/jdk8u-dev/pull/623