Split up test jobs so that they can be run concurrently

[frankieroberto]

Currently all the tests run one after each other, taking just under 5 minutes in total.

Aim here is to run them concurrently, which should roughly half the time it takes to run them all (slowest one is visual regression tests which take about 2.5 mins).

In addition they’ll all get reported on the PR separately, which should make it easier to quickly see which one failed, rather than having to dig into the actions log to work it out.

Before

After