Revert "java_sdk_library: Do not expose stubs implementation jar"

Revert submission 11569833

Reason for revert:  Broke presubmit: b/157231582
Reverted Changes:
Ia99def91e:Improve tracking of exported sdk libraries
If91b4d106:java_sdk_library: Do not expose stubs implementati...
Id6d76e56c:java_sdk_library: Access outputs using tags

Change-Id: I87e459d45ee97e284a9d966d5446305f80627175