RFR: 8361715: (bf) Improve java/nio/Buffer/GetChars.java and migrate to JUnit [v2]

[Brian Burkhalter]

On Tue, 15 Jul 2025 15:29:20 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

> > @bplb Do you mind checking how this overlaps with existing tests?
> 
> Will do.

It looks like some of the range tests and the char get test overlap with `BasicChar` and `GetChars`, some of the `chars` test with `Chars`, and some of the slice testing with `StringCharBufferSliceTest`. Overall this test is focused on the correctness of the methods defined by `CharSequence` as manifested in the `CharBuffer` implementation.

The `testGetChars_range` sub-test helped me identify a problem in my PR #26251 which I then fixed.

All in all I think it adds extra coverage and is neither resource intensive nor slow.

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PR Comment: https://git.openjdk.org/jdk/pull/26282#issuecomment-3076100207