437298: Increase parent forked process timeout again

* Increase to three hours based on evidenc from local run of Bugzilla
tests.

Task-Url: https://bugs.eclipse.org/437298
Change-Id: Ic2c468ef28acdc1759a3242c0c8a7caacdcde5c0
Signed-off-by: Miles Parker <milesparker@gmail.com>

1 file changed