Import quick fix: support extension iterator function

#KT-34303 Fixed

idea/testData/quickfix/autoImports/iteratorOperator.after.kt

@@ -0,0 +1,12 @@
+// "Import" "true"
+// ERROR: For-loop range must have an 'iterator()' method
+// WITH_RUNTIME
+
+package bar
+
+import foo.Foo
+import foo.iterator
+
+fun foo(start: Foo, end: Foo) {
+    for (date in start<caret>..end) {}
+}

idea/testData/quickfix/autoImports/iteratorOperator.before.Dependency.kt

@@ -0,0 +1,7 @@
+package foo
+
+class Foo : Comparable<Foo> {
+    override fun compareTo(other: Foo): Int = TODO()
+}
+
+operator fun ClosedRange<Foo>.iterator(): Iterator<Foo> = TODO()

idea/testData/quickfix/autoImports/iteratorOperator.before.Main.kt

@@ -0,0 +1,11 @@
+// "Import" "true"
+// ERROR: For-loop range must have an 'iterator()' method
+// WITH_RUNTIME
+
+package bar
+
+import foo.Foo
+
+fun foo(start: Foo, end: Foo) {
+    for (date in start<caret>..end) {}
+}