RFR: 8354343: Hardening of Currency tests for not yet defined future ISO 4217 currency

[Naoto Sato]

On Mon, 21 Apr 2025 21:51:35 GMT, Justin Lu <jlu at openjdk.org> wrote:

> Please review this PR which improves future currency checking for ISO 4217 currencies.
> 
> Checking for a currency that should not yet exist in the set of available currencies is already done.
> It should also be explicitly checked that such a currency can not be instantiated as well via the String getter.

LGTM. I think this JIRA issue and the previous test improvement one can be linke to [JDK-8321480](https://bugs.openjdk.org/browse/JDK-8321480), and both have `iso4217` lables.

test/jdk/java/util/Currency/ValidateISO4217.java line 183:

> 181:         setUpPatchedClasses();
> 182:         setUpTestingData();
> 183:         setUpNotYetDefined();

It may be clearer to move this inside `setUpTestingData()`, and modify the comment there

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PR Review: https://git.openjdk.org/jdk/pull/24782#pullrequestreview-2782347271
PR Review Comment: https://git.openjdk.org/jdk/pull/24782#discussion_r2053062123