Revert "Added TypeParameters property to IType (for consistency with the"

This reverts commit 74e78184739ce413c82c932ffd4198dda8535c6a.

Conflicts:
	ICSharpCode.NRefactory/TypeSystem/Implementation/AbstractResolvedTypeParameter.cs
Changed C# invocation result that the reduced extension method has
it's own property.
Adjusted unit tests to the new invocation resolve result.