RenderStates regression

Commit I9bd1eadd37e8addf740a4b85b2318f9be269fedb introduced problems, as it does not allow more than one RenderState of each type. 

https://codereview.qt-project.org/c/qt/qt3d/+/268096

This causes problems if you for instance have multiple clipping planes at the same time. Before this commit this was not a problem, now only one of the clipping planes will be active.

The change also introduced problems for me related to transparency. I've found that it is because it allows only the first BlendEquationArgumentsMask. I may be able to change my code to avoid this one, but at least for the clipping planes I see no workaround.