Layoutlib tests now check methods return value [DO NOT MERGE]

The change is a cherry-pick from klp-dev.

The change also fixes the errors found by fixing the tests.

Change-Id: I87cef323c4eaee4e9f60475f01156b276593fa50
(cherry-picked from commit bdd0ad79b9b027280bd371c7b6795b04ed89ac8f)
3 files changed