Remove redundant receiver in "Change function signature" quick fix

So #KT-12298 Fixed

idea/testData/quickfix/override/nothingToOverride/removeFunctionReciever.kt.after

@@ -0,0 +1,8 @@
+// "Change function signature to 'fun x(s: String)'" "true"
+open class A {
+    open fun x(s: String) {}
+}
+
+class B : A() {
+    <caret>override fun x(s: String) {}
+}