Migrate the tasks and infrastructure to kotlin 1.3.41

[belyaev-mikhail]

• KotlinAsFirst
• Random tests (major change)
• Test runner
• Test runner plugins (maven, gradle?)

[belyaev-mikhail]

Why migrating random tests is a major change: there is a new version of kcheck with shrinking, which is very desirable for us.

[mglukhikh]

I think the target version should be 1.3.41, it's already available.

[mglukhikh]

I migrated base repository to 1.3.41 and fixed some style warnings, but no more yet.