RFR: 8368845: x-IBM930 uses incorrect character for Hex 42 60

[Naoto Sato]

Fixing a charset en/decoder for x-IBM930. There was a "temporary" mapping for the said code point for the backward compatibility (as of  JDK7). Since the issue requests the "correct" mapping, I believe we can replace the temporary one with the correct mapping.

-------------

Commit messages:
 - initial commit

Changes: https://git.openjdk.org/jdk/pull/27594/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27594&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8368845
  Stats: 15 lines in 3 files changed: 0 ins; 13 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/27594.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27594/head:pull/27594

PR: https://git.openjdk.org/jdk/pull/27594