Add an autogenerated notice to annotation stubs

Bug: 199522401
Test: Re-generated existing stubs.
Change-Id: I26fc57b880b078af360a6215a7dd7ee6ae82b4e8
Merged-In: I26fc57b880b078af360a6215a7dd7ee6ae82b4e8
(cherry picked from commit 1e1a46dd954fc416580c5a452f87064cfbdd353e)
12 files changed