Runtime: automated end-to-end integration tests

[camerondurham]

Create end-to-end integration tests for limiting behavior. Should create runner struct and send code that will test the num procs limit, timeout limit and other limits as needed.

Requirements:

1. verify runtime agent returns an error when program exceeds timeout limit
   1. and that execution does not exceed TimeoutLimit + epsilon
2. verify runtime agent returns an error when program exceeds max num procs limit
   1. (note: this will be hard to verify at an OS level, at least returning an error should be okay for now)
3. verify runtime agent returns an error when program exceeds max file size creation limit