"Create abstract function" quick fix: don't suggest it if super classes are not writable

#KT-40215 Fixed

idea/testData/quickfix/createFromUsage/createFunction/call/abstract/notWritableAbstractSuperclass.kt

@@ -0,0 +1,9 @@
+// "Create abstract function 'bar'" "false"
+// ACTION: Create function 'bar'
+// ACTION: Rename reference
+// ERROR: Unresolved reference: bar
+class Foo : Runnable {
+    override fun run() {
+        <caret>bar()
+    }
+}