Fixed remaining test cases from SampleTests.cs

<h4>Summary</h4>
Previous PR (https://github.com/DynamoDS/Dynamo/pull/2111) was having conflicts and it was showing lots of changes in repo because of restructure work. So I just created new branch and resolved conflicts.

<h4>Changes in Test Cases</h4>
- Fix for the defect http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-4041
- Removed few test cases which were doing the same as what we have already covered in other test cases.

<h4>Reviewer</h4>
@ikeough, @Randy-Ma, @lukechurch