Test arm7 on Actions with qemu

[mmarchini]

No intention of dropping Jenkins ARM tests for now, but this should give us better coverage on Actions as well as serve as a testing ground for using qemu instead of bare metal hosts. Maybe after some time if we gather enough confidence in this method we can re-evaluate how we do those tests in Jenkins.

---

👀

(I might be derailing this issue, will open a tracking issue on nodejs/node)

Originally posted by @mmarchini in nodejs/TSC#931 (comment)

[sxa]

We should also consider that it's possible to run arm32 code on mosts aarch64 hosts (The exception being ThunderX aarch64 hosts and while I believe we have some they will soon be replaced) which would be significantly quicker and potentially quite feasible with node being a static binary - we may also be able to increase testing coverage. There may be some side effects if parts of the tests use uname or similar outside node to detect the architecture though.

[EDIT: Doesn't quite work with the node executable on first attempt but I suspect the issue is easily surmountable]