<i18n dev> RFR: 8301991: Convert l10n properties resource bundles to UTF-8 native

[Justin Lu]

This PR converts Unicode sequences to UTF-8 native in .properties file. (Excluding the Unicode space and tab sequence). The conversion was done using native2ascii.

In addition, the build logic is adjusted to support reading in the .properties files as UTF-8 during the conversion from .properties file to .java ListResourceBundle file.

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

Commit messages:
 - Write to ASCII
 - Read in .properties as UTF-8, but write to LRB .java as ISO-8859-1
 - Compile class with ascii (Not ready to make system wide change)
 - Toggle UTF-8 for javac option in JavaCompilation.gmk
 - CompileProperties converts in UTF-8
 - Convert .properties from ISO-8859-1 to UTF-8

Changes: https://git.openjdk.org/jdk/pull/12726/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12726&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8301991
  Stats: 29093 lines in 490 files changed: 6 ins; 0 del; 29087 mod
  Patch: https://git.openjdk.org/jdk/pull/12726.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12726/head:pull/12726

PR: https://git.openjdk.org/jdk/pull/12726