Change Signature: Support conversion between extension and non-extension functions

idea/testData/refactoring/changeSignature/AddNewReceiverConflictBefore.kt

@@ -0,0 +1,13 @@
+fun length(): Int = 1
+
+fun <caret>foo(k: Int): Boolean {
+    return length() - k > 0
+}
+
+class X(val k: Int) {
+    fun length() = 2
+}
+
+fun test() {
+    foo(2)
+}