RFR: 8301991: Convert l10n properties resource bundles to UTF-8 native [v5]

[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.

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

  Close streams when finished loading into props

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Changes:
  - all: https://git.openjdk.org/jdk/pull/12726/files
  - new: https://git.openjdk.org/jdk/pull/12726/files/007c78a7..19b91e6b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12726&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12726&range=03-04

  Stats: 15 lines in 3 files changed: 6 ins; 1 del; 8 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