Use boot image for all tests instead of core.art.

Test: m test-art-host-gtest
Test: test.py -b -r --host --optimizing
Test: mmma art/tools/ahat
Test: (the tests above do not build core.art)
Bug: 147817558
Bug: 147819342
Change-Id: I412fa140e78fd3769696a6635b896b1cf975edd6
7 files changed