Remove redundant setting of DistFiles by java.Library

A previous change handles dist properties automatically for all module
types and as a result has made the java.Library setting of DistFiles
redundant so this change removes that and the tests that duplicate
tests of the general mechanism.

Test: m nothing
      m dist sdk - before and after this change, compare result to
      make sure that there are no significant differences.
Bug: 174226317
Change-Id: Ib79a3bdd46897efd84a9c456c37c374bd6036303