Fix a few  serialization failures due to deprecated nodes.

This commit fixes the remaining failures under ```Dynamo.Tests.SerializationTests``` test suite:

```
Dynamo.Tests.SerializationTests.TestStringFileName
Dynamo.Tests.SerializationTests.TestStringInput
Dynamo.Tests.SerializationTests.TestSublists
Dynamo.Tests.SerializationTests.TestVariableInput
```
And some failures under ```Dynamo.Tests.UI.RecordedTestsDSEngine``` test suite:
```
Dynamo.Tests.UI.RecordedTestsDSEngine.Defect_MAGN_904
Dynamo.Tests.UI.RecordedTestsDSEngine.TestBasicCodeBlockNodePortCreation
Dynamo.Tests.UI.RecordedTestsDSEngine.TestConvertAllNodesToCode
Dynamo.Tests.UI.RecordedTestsDSEngine.TestConvertAllNodesToCodeUndo
Dynamo.Tests.UI.RecordedTestsDSEngine.TestConvertAllNodesToCodeUndoRedo
Dynamo.Tests.UI.RecordedTestsDSEngine.TestVerifyRuntimeValues
```