4.7.137 regression

After upgrading to Moq 4.7.137 the following scenario breaks:

```c#
public void Main()
{
	new Mock<IBreak>().Object;
}

public interface IBreak
{
	void DoStuff<T>(Implementation1<T> a);
	void DoStuff<T>(Implementation2<T> a);
}

public abstract class BaseType<T>
{
}

public class Implementation1<T> : BaseType<T>
{
}

public class Implementation2<T> : BaseType<T>
{
}
```
