Provide specific GitHub workflow to build and test JDK 25 on CI

[apupier]

part of #7862

I mainly copied the ci-build.yaml and modified:

• use the JDK 25 instead of JDK 17
• remove integration-tests-alternative-jdk section
• change triggers: launch one time per week for now, allow to launch manually and launch for PR on a jdk25 branch

I think it will be useful to start having tests running on CI to have an overview of what is the statu and better to keep it separated from normal flow until it is ready to not pollute "normal" flow

[jamesnetherton]

Please add the workflow file into paths-ignore for ci-build.yaml & pr-validate.yml.

I think it will be useful to start having tests running on CI to have an overview of what is the statu and better to keep it separated from normal flow until it is ready to not pollute "normal" flow

Yeah, I think this is an ok compromise, given that we are already 'maxed out' on the number of concurrent jobs in the main CI workflow. It'll be good to get an initial set of JDK 25 issues and starting working through them.