<i18n dev> RFR: JDK-8210410: Refactor java.util.Currency:i18n shell tests to plain java tests

[Justin Lu]

Please review this PR which converts the shell test, _java/util/currency/PropertiesTest.sh_ to a normal java test.

This test is a test runner that launches test methods from _PropertiesTest.java_. It tests both the ways to supersede the default currencies, that is, either using a custom properties file under the lib directory, or setting the path to a custom properties file via the system property.

In addition to the conversion, I have updated the test so that the `PropertiesTest` methods are ran by both the default test JDK and the newly created writable JDK, not just the writable JDK.

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Commit messages:
 - resolve conflicts
 - init

Changes: https://git.openjdk.org/jdk/pull/16787/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16787&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8210410
  Stats: 303 lines in 2 files changed: 159 ins; 144 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/16787.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16787/head:pull/16787

PR: https://git.openjdk.org/jdk/pull/16787