Supported KProperty2 and KMutableProperty2 for delegated properties

Consider this code:
object Delegate {
    operator fun getValue(t: Any?, p: KProperty<*>): String {
        return ""
    }
}

class A {
    val String.ext by Delegate
}

then the type of <p> is KProperty2 (it has 2 receivers).

Test fix + review fixes

compiler/frontend/src/org/jetbrains/kotlin/types/expressions/DoubleColonExpressionResolver.kt

@@ -772,7 +772,7 @@ class DoubleColonExpressionResolver(
                         val setter = descriptor.setter
                         setter == null || Visibilities.isVisible(receiverType?.let(::TransientReceiver), setter, scopeOwnerDescriptor)
                     }
-                    reflectionTypes.getKPropertyType(Annotations.EMPTY, receiverType, descriptor.type, mutable)
+                    reflectionTypes.getKPropertyType(Annotations.EMPTY, listOfNotNull(receiverType), descriptor.type, mutable)
                 }
                 is VariableDescriptor -> null
                 else -> throw UnsupportedOperationException("Callable reference resolved to an unsupported descriptor: $descriptor")