[jdk8u-dev] RFR: 7102969: currency.properties supercede not working correctly

[Severin Gehwolf]

This is a backport of JDK-7102969 and JDK-8157138 both of which were done as a single patch in JDK 9 (and also included JDK-8149452 which isn't part of this backport because it changes CLDR related things which I think are too risky to backport and only applying those hunks fails the newly added test for it). The reason why I propose to backport this is:

1. Oracle backported it to 8u461
2. It's a more thorough fix of [JDK-8353433](https://bugs.openjdk.org/browse/JDK-8353433) which got added to avoid a test failure for an ISO 4217 Amendment 176 update. See [JDK-8353579](https://bugs.openjdk.org/browse/JDK-8353579) and [this comment](https://bugs.openjdk.org/browse/JDK-8353433?focusedId=14771442&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-14771442) for details.

I've mostly applied hunks manually and omitted the test for JDK-8149452 and the related `jdk/make/src/classes/build/tools/cldrconverter/CLDRConverter.java` changes.

Since this also fixes JDK-8353433, the change to the `CurrencyData.properties` has been revered (see separate commit). Backports of JDK-7102969 and JDK-8157138 fix the `java/util/Currency/ValidateISO4217.java` test as well.

Testing:
- [x] `jdk/test/java/util/Currency/` tests

Thoughts? Please review! Thanks in advance.

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Commit messages:
 - 7102969: currency.properties supercede not working correctly
 - Revert "8353433: XCG currency code not recognized in JDK 8u"

Changes: https://git.openjdk.org/jdk8u-dev/pull/660/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=660&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-7102969
  Stats: 389 lines in 7 files changed: 289 ins; 42 del; 58 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/660.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/660/head:pull/660

PR: https://git.openjdk.org/jdk8u-dev/pull/660