Merge "Revert "Revert "Normalize building generic system image with...
Merge "Revert "Revert "Normalize building generic system image with treble-common.mk""" into oc-dev am: 40b59b89 -s ours
am: afb44804
Change-Id: I6d4ddc0436dd4602d623396f70deae344e4ef2a8