tests/check/pipelines/simple-launch-lines.c: Attempt to 'fix' spuriously failing test case: it seems like the timeout...

Original commit message from CVS:
* tests/check/pipelines/simple-launch-lines.c: (test_stop_from_app):
Attempt to 'fix' spuriously failing test case: it seems like the
timeout of half a second is simply too small when the system is under
load otherwise, and the timeout doesn't really seem to serve any
particular purpose here. Give the pipeline a few seconds to preroll
first, and then give it another half a second to go from PAUSED to
PLAYING and marshal the message into the main thread.