RFR: 7904000: Update to build with JDK 17

[Jan Lahoda]

On Mon, 19 May 2025 19:10:34 GMT, Christian Stein <cstein at openjdk.org> wrote:

> Please review this change to update to build of `jtreg` with JDK 17.
> 
> Note that we still keep the `--release 8` for agent classes, and `--release 11` for tool classes as-is. That means, the runtime required to launch `jtreg` is unchanged.
> Note also, that some tests may require (bundled) external libraries, such as AsmTools 8.1, which moved to Java 17 as their baseline.
> 
> This change also sets the version of `jtreg` to `7.6`, the next release number.

Looks OK to me.

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Marked as reviewed by jlahoda (Lead).

PR Review: https://git.openjdk.org/jtreg/pull/264#pullrequestreview-2852962799