Fix visibility issues with android.test.mock.stubs

This ensures that the API definitions for the android.test.mock package
matches the definitions in the api/current.txt file.

Bug: 30188076
Test: make update-api
(cherry-picked from commit bd97e3dd4e5d395f336114016b000ef3cfb26053)

Merged-In: Id325b8cf2f189117ac4cfe7634095ab710eee004
Change-Id: Id325b8cf2f189117ac4cfe7634095ab710eee004
3 files changed