Rework CI: run all examples

[juherr]

CI changes from #1599, which should not include these updates.
As expected (and already addressed in #1599), the Gradle Android example does not work with Java 17/21.

[joelittlejohn]

@juherr Thanks so much for all the work you have been doing on this recently! Please do try to keep changes focused on one improvement at a time, as it makes reviewing much easier and allows things to be merged much more quickly. Splitting out these changes was a useful step. Please resist the urge to keep expanding the scope of what you're doing to fix other things at the same time - we can always land more PRs.

Am I right in thinking that the path forward now is to merge this PR first (and accept that those two examples will fail) then rebase #1599 and merge that afterwards?

[juherr]

@joelittlejohn These changes originated as part of the experiments for #1599 and have since been refined into the version you see here.
This PR is required for #1599, and the Android Gradle example currently fails on Java 17 and 21 but works correctly with #1599 as demonstrated there.

[joelittlejohn]

@juherr So we merge this one first, right?

[juherr]

@joelittlejohn Yes. The failling jobs should be fixed by the next pull request.

[ctrimble]

@juherr I am closing this PR, as the same changes are coming from #1599 and I have already started to break that down into smaller chunks. I will continue to peal history off of that PR, until we get it into a position where the actual JDK update can be reviewed.