KT-2596 Can't use iterator in for-loop

#KT-2596 fixed

compiler/testData/codegen/regressions/kt2596.kt

@@ -0,0 +1,7 @@
+fun box(): String {
+    val iterator: Iterator<Int> = (0..0).iterator()
+    for (i in iterator) {
+        return "OK"
+    }
+    return "fail"
+}