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

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

@@ -0,0 +1,10 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+class My {
+    constructor(arg: Int?) {
+        run {
+            var x = arg
+            if (x == null) return@run
+            x.hashCode()
+        }   
+    }
+}