Check results of Algorithm tests

The UnitTestAlgorithm test was running several device algorithms, but it was not checking the results of any of them. (In fact, it was not even setting values in the input arrays.) So, it verified that the execution did not crash, but did not verify correctness.

Add checks to the results to make sure this executed correctly. (Part of the reason for this change was a warning that popped up because a result value was never used.)