* Implemented instancing for the drawInstanced test and confirmed that test values taken at specific pixel location match expected values

* Removed writeImage() helper function as this is for debugging only

* Factored out shared test code and wrapped tests inside a base class with derived structs for each individual draw call variant; Added a test for indexed, instanced draws but test is currently not working correctly

* Indexed instancing test finish and working; Further refactor to move code that fills the test result array and creates the vertex and color buffers to the base test class

* Commented out image dump helper function at the top as it may still be needed for the remaining draw tests

* Added a new struct derived from the base test class for testing indirect but non-indexed draws; Moved required command signatures for indirect draws into D3D12Device to ensure they continue to exist outside of their respective draw calls; Moved command signature creation into D3D12Device::initialize(); Small consistency cleanup changes

* Added working indexed indirect draw call test

* Moved expectedResult and compareComputeResult() call into getTestResults() and renamed to checkTestResults()

* Rerun tests