Use Splitic test runner
What does this MR do?
Uses Splitic to run tests, and generate junit and coverage reports
Why was this MR needed?
We previously relied on shell scripts for much of this, and it was hard to build on top of and make efficient
What's the best way to test this MR?
All jobs should pass, with coverage and junit reports being generated
What are the relevant issue numbers?
Closes #30835 (closed)
Closes #30852 (closed)
Closes #4467 (closed)
Edited by Arran Walker