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

compiler/testData/diagnostics/tests/smartCasts/falseReceiverSmartCast.fir.kt

@@ -0,0 +1,15 @@
+open class SuperFoo {
+    public fun bar(): String {
+        if (this is Foo) {
+            superFoo()
+            return baz()
+        }
+        return baz()
+    }
+
+    public fun baz() = "OK"
+}
+
+class Foo : SuperFoo() {
+    public fun superFoo() {}
+}