Add profman option to generate a random profile based on dex files.

Extends --generate-test-profile to make a randomized profile based on a
set of dex files. Will randomly incorporate classes and methods from all
the dex files given. Can be given a random seed for reproducibility.

Bug: 36107940
Test: mm test-art-host-gtest-profile_assistant_test
Change-Id: Ib0e54bde5317439516a39afa41c3c9980834fa54