Added test case and .xml file for defect MAGN1463
added test case for MAGN1971 with supporting file
added test case for MAGN 1292 and supporting .dyn file
Deactivate redefined graphnodes

1. Graphanodes that are redefined should be inactive
2. Check for graphnode redefinition in the same scope
Refactor graphnode redefinition routine to HandleGraphNodeRedefinitionInScope()
Liverunner testcase to simulate revit node force-execution bug

Simulates the defect from:
http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-4642
Harden TestLoadNoNamespaceClass

TestLoadNoNamespaceClass was also testing the ability to load the FFITarget. This isn't ideal for a system test.

This PR hardens the test so that if the library is already loaded it doesn't attempt to reload it.

It should be followed up by a cleanup PR to:

   - Add a support method to libraryServices: IsLibraryLoaded
   - Fix the libraryServices.Reset support method
Merge pull request #2427 from theanh0512/MAGN1292

added test case for MAGN 1292 and supporting .dyn file
Merge pull request #2426 from theanh0512/MAGN1971

added test case for MAGN1971 with supporting file
Merge pull request #2493 from DynamoDS/fixFlakyFFILibraryTest

Harden TestLoadNoNamespaceClass
Merge pull request #2425 from theanh0512/MAGN1463

Added test case and .xml file for defect MAGN1463
Merge pull request #2469 from junmendoza/VMStability

Deactivate redefined graphnodes
Merge branch 'master' of https://github.com/DynamoDS/Dynamo into ShutdownSequence