Merge from Widevine repo of http://go/wvgerrit/142150 (part 1)
For an EVT device, without a keybox or with a test keybox, we want it
to fall back to L3. However, when running the unit or integration
tests it should continue running tests with test keybox. This will
allow us to test L1 oemcrypto on an EVT device, while still using an
EVT device for dogfooding video content at the L3 level.
The original CL modified the HIDL and non-HIDL plugin, so this is the
hand cherry-pick.
Bug: 210807585
Change-Id: I85b96f127abe30f8f061b242f7580fa8f6c01776
04e1d8efbc