[jdk15u-dev] RFR: 8247432: Update IANA Language Subtag Registry to Version 2020-09-29

[Yuri Nesterenko]

This update should be ported to 15u, too.

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Commit messages:
 - Backport ae0ca743f5646a5312566a6a65ec8929fca4b372

Changes: https://git.openjdk.java.net/jdk15u-dev/pull/53/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk15u-dev&pr=53&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8247432
  Stats: 52 lines in 2 files changed: 44 ins; 5 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk15u-dev/pull/53.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk15u-dev pull/53/head:pull/53

PR: https://git.openjdk.java.net/jdk15u-dev/pull/53