Creating javadocJar task for every project produces lots of unnecessary
tasks, some project don't even have code. Jar task without outDir
property set fails idea import with gradle 5.0+
Required as a workaround for Proguard bug
https://sourceforge.net/p/proguard/bugs/664/
When processing bytecode generated by Kotlin compiler for constructor
call with stack spilling during arguments evaluation, ProGuard performs
an equivalent transformation for the bytecode, but emits invalid stack
frame information.
In JVM 1.6, such invalid stack frames are ignored and re-evaluated by
JVM during bytecode verification.
In JVM 1.8, such invalid stack frames cause VerifyError.