Revert "Generate runtime stubs in droidstubs"

Revert submission 2929615

Reason for revert: b/328225000

Reverted changes: /q/submissionid:2929615
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:17f01d976acd757cb6afabba3f3606a6b25d0ecf)
Merged-In: Ifbec11417103c96b37a4da18dfc9fda73f654d8f
Change-Id: Ifbec11417103c96b37a4da18dfc9fda73f654d8f
24D1-dev is based on 24Q2-release. Therefore, we merged this CL to 24D1-dev.