RFR: 8369078: Fix faulty test conversion in IllegalCharsetName.java

[Alan Bateman]

On Fri, 3 Oct 2025 22:14:33 GMT, Justin Lu <jlu at openjdk.org> wrote:

> This PR corrects two instances of `Charset.isSupported` which were inadvertently converted to `Charset.forName` in _test/jdk/java/nio/charset/Charset/IllegalCharsetName.java_ during [JDK-8369078](https://bugs.openjdk.org/browse/JDK-8369078).

Marked as reviewed by alanb (Reviewer).

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

PR Review: https://git.openjdk.org/jdk/pull/27631#pullrequestreview-3301590841