Revisit our BrowserStack browsers

Currently, we test the latest versions of all the browsers we support.

While that's fine, it only covers half of the picture. Also, in the case of Edge, we are no longer testing on the old Edge which is still supported.

This issue is present on both master and v4-dev. I think we better test both the minimum browser versions and the latest ones. It will make tests slower, but after we split the actions, this should be a lot more bearable.