<i18n dev> RFR: 8298808: Check `script` code on detecting the base locales

[Naoto Sato]

Fixing `CLDRConverter` build tool to not regard [new locales](https://github.com/unicode-org/cldr/pull/2508/files#diff-94cbefde02914335da884f768063a06a84ad651ee4e56cdb1cb90625d7776731) introduced in CLDR 43 as one of the base locales. Otherwise they would incorrectly go into `java.base` module, then a test case fails.

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Commit messages:
 - 8298808: Check `script` code on detecting the base locales

Changes: https://git.openjdk.org/jdk/pull/11684/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11684&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8298808
  Stats: 12 lines in 2 files changed: 9 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/11684.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11684/head:pull/11684

PR: https://git.openjdk.org/jdk/pull/11684