Add art_defaults to dexlayout

The build rule defaults for dexlayout targets didn't include defaults
from the ART project.  Because of this ART_TARGET_* weren't defined,
among other problems

Bug: 35800981
Test: make -j 40 test-art-host
Change-Id: Ic528bfc6b622fa9b4f5c0ddf883f15912641b720
3 files changed