DataflowRunner writes to System.out instead of logging

DataflowRunner writes two lines to stdout for every job, which bypasses the logger setup. This is slightly annoying, especially if many jobs are started programmatically.

Imported from Jira [BEAM-7977](https://issues.apache.org/jira/browse/BEAM-7977). Original Jira may contain additional context.
Reported by: sgrj.

Start by locating DataflowRunner and the two writes that send a line to stdout. Trace the surrounding logging setup, then verify that the job messages use the logger instead of stdout and that the two lines no longer appear on standard output.

Written by the indexing model from the issue text.