Store `Charset` object in `jnuEncoding` and use `String(byte[], Charset)` and `String.getBytes(Charset)` instead of passing the charset name.
------------- Commit messages: - 8305746: InitializeEncoding should cache Charset object instead of charset name Changes: https://git.openjdk.org/jdk/pull/13499/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13499&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8305746 Stats: 49 lines in 1 file changed: 18 ins; 14 del; 17 mod Patch: https://git.openjdk.org/jdk/pull/13499.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/13499/head:pull/13499 PR: https://git.openjdk.org/jdk/pull/13499
