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

compiler/testData/diagnostics/tests/smartCasts/varnotnull/iterations.fir.kt

@@ -0,0 +1,14 @@
+data class SomeObject(val n: SomeObject?) {
+    fun doSomething() {}
+    fun next(): SomeObject? = n    
+}
+
+
+fun list(start: SomeObject) {
+    var e: SomeObject? = start
+    while (e != null) {
+        // While condition makes both smart casts possible
+        e.doSomething()
+        e = e.next()
+    }
+}