Enable multi-dex content per file in dexlist/dump.

Rationale:
Unlike the original Dalvik-based utilities, the Art-based
utilities are able to extract multi-dex content from one file.
So no need for any artificial restriction on number of dex files.

Bug: 22322814
Change-Id: I7c603d22c7e0caa5ae712b905d9bb83982f1b918