avocado.job: Fix deadlock in TestRunner.run() [v2]

multiprocessing.Queue().put() is asynchronous and in case the test died
critically before the put() was executed, TestRunner.run() waited for
infinity for early_state. This patch uses
multiprocessing.queues.SimpleQueue(), where it's guaranteed that after
executing put() the data are already in the SimpleQueue.

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>

v1: https://github.com/avocado-framework/avocado/pull/286

Changelog:

    v1: Use multiprocessing.queues.SimpleQueue as queue instead of executing
        the process again
    v1: Reorganize imports (sorry, Eclipse did that automatically, but now it's 
        sorted alphabetically ;-) )
So, the fix definitely works! I was testing if a simpler fix would be possible, such as trying to make the `queue.put(early_state)` synchronous by adding `block=True`, but it doesn't work like I thought it would.

To me it's an ACK.