Parallel job coverage is reported on the next run

[efaulhaber]

When running parallel coverage jobs and starting the next run before the previous one is finished, the reports of the previous run show up on the newest one instead of the one they belong to.

Check out trixi-framework/Trixi.jl#400. I started a run with all tests and then removed most of the tests. The newest run reports for example 1d and 3d tests even though I removed them all. The previous run doesn't report any individual coverage jobs, they all show up on the latest run. Also, the coverage is reported to remain the same although I removed most of the tests.

Here you can clearly see that more coverage reports than test runs show up: