[jdk25u] RFR: 8357141: Update to use jtreg 7.5.2

[Aleksey Shipilev]

On Wed, 1 Oct 2025 16:15:35 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Upgrading jtreg to 7.5.2 to match mainline, on our way to jtreg 8. It is a separate commit, so that we can backout jtreg 8 upgrade separately, if we need.
> 
> Additional testing:
>  - [x] GHA
>  - [x] Linux AArch64 server fastdebug, `all` with jtreg-7.5.2

Push approval granted.

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PR Comment: https://git.openjdk.org/jdk25u/pull/258#issuecomment-3372241757