Deterministic aquery details in mixed builds

This change constitutes a number of fixes which cause mixed builds to
have deterministic ninja file output:

1. Depsets are identified based on a hash of their contents instead of
   an arbitrary ID integer from Bazel
2. Depset definitions in the ninja file are sorted by the above hashes
3. BuildStatements (action information from Bazel's aquery) are sorted
   by their contents

Test: Ran `USE_BAZEL_ANALYSIS=1 m nothing` three times and verified the
md5sum of out/soong/build.ninja was identical all three runs.
Test: mixed_droid

Change-Id: Iffdf6cc62c31d76fbbfa78726827497516171f4f