SF: Do not assume existence of primary display

This CL adds checks and assertions to DisplayDevice and IBinder lookup
for the primary display. It also removes HWC_DISPLAY_PRIMARY constants
in the SurfaceFlinger class.

Bug: 74619554
Test: libsurfaceflinger_unittest
Change-Id: I966d3fd8843e0392cc48a39610d2105d80453747
2 files changed