Add @NonNull annotation to Builder.addXXX args

API guidelines is for each non-primitive arg to have a nullablility annotation.
Since it's very rate for collections to permit null values, just assume
collections only accept @NunNull emenents for now.

Fixes: 144725154
Test: . frameworks/base/tests/Codegen/runTest.sh
Change-Id: I333327490bd8eb9bb031f062c80283bd405173af