Push OverlayDeviceTests onto /system

Since OverlayDeviceTests needs to use the OverlayManager API directly,
push the test APk onto the system image and reboot the device before
running tests.

Bug: 119916381
Test: atest OverlayDeviceTests
Change-Id: I8f54e1532902b984e32da68ed8aa32bf6c5b9272
5 files changed