1. Updated "Watch.Process" method to return an empty "WatchNode" if all else failed
2. Added test case "Defect_MAGN_883" that simulate the user scenario
Added TODO comment and marked test case "Defect_MAGN_883" as ignored
Merge pull request #851 from Benglin/MAGN883

Fix: https://github.com/ikeough/Dynamo/issues/832