Move APK install/uninstall to tradefed target_preparer

Move APK install/uninstall to tradefed target_preparer

We shouldn't be doing this by hand with a modern tradefed. The previous
implementation was also insanely wasteful -- we'd uninstall and
reinstall the target package every 1K tests.

V3: Adjust testrunner unit tests to not expect installs/uninstalls to
happen
V4: Remove time claim. There is still a significant pause between batches.

Change-Id: Ida67984ce45e60eb025fabfd997c7a9015496333
(cherry picked from commit c2b068c5a09f883f3a6af0e7d4aff639e8f8a070)
Merged-In: Ida67984ce45e60eb025fabfd997c7a9015496333