Fix Revit Test failures due to test data restructuring

- Now Revit test data is under test\System\ folder
- Updated all test initialization calls to consider this path for revit
test data.
Merge pull request #3266 from Conceptual-Design/DynamoRevit2014

Fix Revit Test failures due to test data restructuring
Merge pull request #3267 from DynamoDS/DynamoRevit2014

Merge pull request #3266