android.test.runner is using AndroidTestCase.[set|get]TestContext
methods from android.test.base. The problem is that the methods are
internal APIs and this is preventing us from hiding the impl library of
android.test.base to others.
Marking those two methods as APIs.
Bug: 157007292
Test: m
Test: android.test.runner
Change-Id: I8ea5421723a4a40d580956e5ceb51be70253f0eb
04f520d136