RFR: 8301991: Convert l10n properties resource bundles to UTF-8 native [v2]

[Justin Lu]

> JDK .properties files still use ISO-8859-1 encoding with escape sequences. It would improve readability to see the native characters instead of escape sequences (especially for the L10n process). The majority of files changed are localized resource files.
> 
> This change converts the Unicode escape sequences in the JDK .properties files (both in src and test) to UTF-8 native characters. Additionally, the build logic is adjusted to read the .properties files in UTF-8 while generating the ListResourceBundle files.
> 
> The only escape sequence not converted was `\u0020` as this is used to denote intentional trailing white space. (E.g. `key=This is the value:\u0020`)
> 
> The conversion was done using native2ascii with options `-reverse -encoding UTF-8`.
> 
> If this PR is integrated, the IDE default encoding for .properties files need to be updated to UTF-8. (IntelliJ IDEA locks .properties files as ISO-8859-1 unless manually changed).

Justin Lu has updated the pull request incrementally with one additional commit since the last revision:

  Replace InputStreamReader with BufferedReader

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/15694/files
  - new: https://git.openjdk.org/jdk/pull/15694/files/0f3698a5..ceb48bbe

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15694&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15694&range=00-01

  Stats: 18 lines in 2 files changed: 6 ins; 8 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/15694.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15694/head:pull/15694

PR: https://git.openjdk.org/jdk/pull/15694