…tarballs

#4760 unintentionally included extra raw class files in the release tarballs by making the .class file output (instead of the jar) for a streams a dependency of the streams-test-utils. This fixes that issue by instead breaking the circular dependency by using a `compileOnly`/`provided` dependency on those sources and also including the dependency as a test dependency.

I verified by using `gradlew clean installAll releaseTarGzAll`, then checking that the release tarball doesn't have the extraneous files and the installed pom file has the expected dependencies. The dependency on kafka-streams is now in the `test` scope, but that should be fine since a streams application would only use this dependency if it already had a dependency on streams in `compile` (or in weird edge cases the user could handle specifying the right dependencies). This actually seems to even be an improvement over the previous situation where the actual dependency was not expressed in the pom at all (since the dependency was on the sourceSet output rather than the actual project).

Author: Ewen Cheslack-Postava <me@ewencp.org>

Reviewers: Matthias J. Sax <mjsax@apache.org>, Guozhang Wang <wangguoz@gmail.com>, John Roesler <vvcephei@users.noreply.github.com>

Closes #4816 from ewencp/fix-streams-dependencies