devops: run tests on Ubuntu 20.04 arm64 (#11079)
devops: run tests on Ubuntu 20.04 arm64 (#11079)

Since our Docker images for Ubuntu 18.04 and Ubuntu 20.04 are almost
identical, we can avoid testing all permutations.

With this patch, we will run our test only under 2 docker
configurations:
- Ubuntu 20.04 arm64 + root user
- Ubuntu 18.04 x86_64 + pwuser
microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright