ART: Change meaning of run-test's --no-image

Do not test runtime image generation. Instead test running without
an image by disabling image patching.

Bug: 67596919
Test: m test-art-host
Test: art/test/testrunner/run_build_test_target.py art-no-image
Change-Id: Idf6f0368ea94efbc61285457711af896a80e2ffb