SF: Introduce DisplayDeviceCreationArgs

Introduce a structure to hold the arguments used by the DisplayDevice
constructor. This simplifies the injector code used by the test, and
makes it easier to change the arguments without requiring a change to
the test or to the upcoming factory.

Test: atest libsurfaceflinger_unittest
Test: Marlin boots and appears usable
Bug: None

Change-Id: I4c806bf40f8f3c2c00f5115b83c6ab926317d628