Extract Function: Limit the set of allowed containers for the default action

idea/testData/refactoring/extractFunction/defaultContainer/classFunction.kt.after

@@ -0,0 +1,11 @@
+class A {
+    class B {
+        fun foo(a: Int, b: Int): Int {
+            return i(a, b)
+        }
+
+        fun i(a: Int, b: Int): Int {
+            return a + b - 1
+        }
+    }
+}