Caliing DynamicProxy proxy methods with multidimensional array parameters

I noticed that when I created a proxy for an object with a method which takes a 2-dimensional array parameters that the proxy created ok, but when I called the method, that there was an exception due to the proxy method being called with parameter type T[] rather than T[,].

This pull request strengthens the ProxyTypeWithMultiDimentionalArrayAsParameter unit test by actually calling each of the methods of the test class. TypeUtil.GetClosedParameterType is altered so that it returns the correct type for multi-dimensional arrays and the unit test passes. I think that all other unit tests continue to pass.

Hope this helps, Ed.