Remove 3 unused HashMap's. Reported here https://mail.openjdk.java.net/pipermail/core-libs-dev/2021-September/081866.html I did the similar PR to treetenbp and it was merged https://github.com/ThreeTen/threetenbp/pull/155
------------- Commit messages: - [PATCH] Remove unused fields in ThaiBuddhistChronology Changes: https://git.openjdk.java.net/jdk/pull/5917/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5917&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8275197 Stats: 37 lines in 1 file changed: 0 ins; 36 del; 1 mod Patch: https://git.openjdk.java.net/jdk/pull/5917.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/5917/head:pull/5917 PR: https://git.openjdk.java.net/jdk/pull/5917
