Modify `TestStructuredProfilerRowStatistics`: Update null stats tests

[micdavis]

Is your feature request related to a problem? Please describe. The null stats tests in TestStructuredProfilerRowStatistics link need to be updated to use the data that is created in setUpClass link. Currently they are using their own datasets

Describe the outcome you'd like: The null stats tests should use the data initialized in the setUpClass class method, not their own data

[taylorfturner]

Its effectively just pointing to a single data source or is it putting all the various datasets in the setUpClass method to just have them all setup and initialized in the setUpClass (i.e. still have a plethora of datasets just not in the "test" function)? @JGSweets

[jacob-buehler]

pr #898 closed on june 28