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

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt609.fir.kt

@@ -0,0 +1,20 @@
+//KT-609 Analyze not only local variables, but function parameters as well in 'unused values' analysis
+
+package kt609
+
+fun test(a: Int) {
+    var aa = a
+    aa = 324 //should be an 'unused value' warning here
+}
+
+class C() {
+    fun foo(s: String) {}  //should be an 'unused variable' warning
+}
+
+open class A() {
+    open fun foo(s : String) {}  //should not be a warning
+}
+
+class B() : A() {
+    final override fun foo(s : String) {}  //should not be a warning
+}