Parallelise test by timing data on circle ci

[slonka]

https://circleci.com/gh/allegro/envoy-control/tree/run-tests-in-parallel

https://circleci.com/blog/how-to-boost-build-time-with-test-parallelism/ (gradle setup)

[slonka]

Some initial work has been done here: https://github.com/allegro/envoy-control/compare/run-tests-in-parallel-3?expand=1

The main problem seems to be that CircleCI expects a list of test classes to assign each worker a set of them, but I did not find any way to list all test classes in gradle. The workaround I applied was to compile the project and then list all files that match a pattern ./**/*Test.class (remember that in Kotlin there can be more than one class in a .kt file).

When this issue is implemented this problem will be solved: gradle/gradle#2129

[slonka]

Example here: all-of-us/workbench@47fa824#diff-78a8a19706dbd2a4425dd72bdab0502ed7a2cef16365ab7030a5a0588927bf47R322