Ensure injected device has id = -1

To prevent misrepresentation of physical hardware, ensure that injected
events are always coming from the virtual input device, which has device
id = -1.

Check both key events and motion events, since the implementation
handles the 2 cases differently (and therefore, there is room for
error).

Bug: 149845127
Test: atest VerifyInputEventTest
Change-Id: I8fa8a3e3f721b2e55ae9894f16bb4ac4525e8f70