Merge run-test-build.py and art_build_rules.py

These used to be two different processes in bash and python.
It is part of just single step now with no bash-python transitions.

Therefore move the relatively trivial "main" method with the rest
of the build code.

Test: generated build artifacts are identical
Change-Id: I29bd68e3bdc8ad8349b3f054502da06606e76f0a
5 files changed