Feature request: Need to habitually test on pre-release forms of supported target platforms

[erights]

Same issue for agoric-sdk as endojs/endo#2230 describes for endo. Like endo, agoric-sdk CI is not currently run on anything more recent than Node 20. We should at least CI under Node 21, so we have advance warning of problems before Node 22 is released.

endojs/endo#2198 was erroneously closed by endojs/endo#2200 because endojs/endo#2198 only manifested on browsers and we manually tested endojs/endo#2200 on those browsers to "verify" that it was fixed.

However, we are not set up to run our normal yarn test CI tests habitually (or under CI) on those browser engines. We current do our regular yarn test CI testing, where everything was coming up green, but only because the most recent Node we CI is Node 20, and Node 20 does not yet have v8's problematic stack accessor behavior. I separately reopened endojs/endo#2198 until those old tests are fixed, in progress at endojs/endo#2229. But currently I can only verify that endojs/endo#2229 fixes it by running yarn test locally with Node 21.

So, feature request: We should as much as possible run all our normal tests on the pre-release form of all target platforms we support, so we get early warning when we're about to stop working on a release.

Fortunately, in this case, it looks like the src/ fixes from endojs/endo#2200 do still actually fix the endojs/endo#2198 problem. The only remaining problem, being addressed in endojs/endo#2229, is to update the tests. This would indeed have caused CI failures as soon as we would upgrade to support Node 22, but only because the tests are wrong. The code being tested already seems good for Node 21 and thus presumably for Node 22, at least as far as these issues are concerned.