Remove code duplication in cuda real hw vs simulator

[sklam]

There are two devicearray.py files for the cuda backend and there are several methods that are either duplicated or looks very similar. We should consolidate the code to avoid repeating ourselves. The first step may just be moving the duplicated code to a file that the real hw and simulator codepaths can share. In the long term, we should also consider refactoring the interface to reduce the similar looking code.