[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/tests/thisAndSuper/superInExtensionFunctionCall.fir.kt

@@ -0,0 +1,9 @@
+// No supertype at all
+
+fun Any.extension(arg: Any?) {}
+
+class A1 {
+    fun test() {
+        super.extension(null) // Call to an extension function
+    }
+}