Closes https://github.com/ooni/probe/issues/2334.
While there, reinstate integration tests, which were also lost in a previous refactoring. However, only run those tests for linux/amd64 because we can be confident that the Go compiler is WAI for all archs we support.
While there, always use bash for running end-to-end tests.
H/T @ainghazal for discovering and reporting this bug.
The issue at https://github.com/ooni/probe/issues/1741 is that running `docker --platform linux/arm64` segfaults when running `sudo apt-get update -q` inside the `arm64` docker environment.
As far as the `debianrepo` rule is concerned, we can fix the issue by taking advantage of Debian multi-arch. We now configure Debian multi-arch and install the package inside a `debian:stable` environment.
We keep using docker. In principle we could not. But the Ubuntu environment provided by GitHub actions does not support multi-arch for arm. Also, I'd like testing this rule to be possible also locally (where I don't have Debian).
