fix for KT-245

idea/testData/codegen/regressions/kt245.jet

@@ -0,0 +1,32 @@
+fun foo() {
+    val l = java.util.ArrayList<Int>(2)
+    l.add(1)
+
+    for (el in l) {}
+
+    //verify error "Expecting to find integer on stack"
+    val iterator = l.iterator()
+
+    //another verify error "Mismatched stack types"
+    while (iterator?.hasNext() ?: false) {
+        val i = iterator?.next()
+    }
+
+    //the same
+    if (iterator != null) {
+        while (iterator.hasNext()) {
+            val i = iterator?.next()
+        }
+    }
+
+    //this way it works
+    if (iterator != null) {
+        while (iterator.hasNext()) {
+            iterator.next() //because of the bug KT-244 i can't write "val i = iterator.next()"
+        }
+    }
+}
+
+fun box() : String {
+    return "OK"
+}