RFR: 8176706: Additional Date-Time Formats

[Naoto Sato]

Following the prior discussion [1], here is the PR for the subject enhancement. CSR has also been updated according to the suggestion.

[1] https://mail.openjdk.java.net/pipermail/core-libs-dev/2022-January/085175.html

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Commit messages:
 - Removed trailing space
 - Merge branch 'master' into skeleton
 - Tidying up
 - Some more tests
 - Brought back the part that was mistakenly removed
 - Merge branch 'master' into skeleton
 - Reverted IllegalArgumentException back
 - Further cleanups
 - Removed exceptions from ofLocalizedPattern() method, as they are lazily thrown on format()
 - Cleanup
 - ... and 19 more: https://git.openjdk.java.net/jdk/compare/cda9c301...f9311dce

Changes: https://git.openjdk.java.net/jdk/pull/7340/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7340&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8176706
  Stats: 777 lines in 12 files changed: 733 ins; 9 del; 35 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7340.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7340/head:pull/7340

PR: https://git.openjdk.java.net/jdk/pull/7340