RFR: 7903943: Release jtreg 7.5.1 [v3]

[Iris Clark]

On Tue, 4 Feb 2025 18:41:34 GMT, Christian Stein <cstein at openjdk.org> wrote:

>> Please review this change preparing the `7.5.1` release of `jtreg`.
>> 
>> The version number `7.6` will be restored on the main branch after the release; a dedidated `7.5.x` branch was not required, yet.
>> 
>> This change also updates the `CHANGELOG.md` file with noteworthy items. It also removes the detailed description of the now removed `LIBRARY.properties` support from the `7.5` section.
>
> Christian Stein has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove last traces of `LIBRARY.properties`

Marked as reviewed by iris (Reviewer).

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PR Review: https://git.openjdk.org/jtreg/pull/245#pullrequestreview-2593873073