Make com.android.art related tests more realistic

Previously, some tests used "com.android.art.something" as the name of
the APEX containing the ART boot jars but that is not the valid name
for an ART APEX. This change switches that to "com.android.art.debug".

Bug: 171061220
Test: m nothing
Change-Id: I057edc58ae81cdb14076a2d7d117ca1764aa3e52