Resolve callable reference expressions

#KT-1183 In Progress

compiler/testData/diagnostics/tests/callableReference/nestedConstructorFromTopLevel.kt

@@ -0,0 +1,9 @@
+class A {
+    class Nested
+}
+
+fun main() {
+    val x = A::Nested
+
+    x : KFunction0<A.Nested>
+}