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"
+}

compiler/tests/org/jetbrains/jet/codegen/StdlibTest.java

@@ -373,4 +373,8 @@ public class StdlibTest extends CodegenTestCase {
     public void testKt2246() {
         blackBoxFile("regressions/kt2246.kt");
     }
+
+    public void testKt2596() {
+        blackBoxFile("regressions/kt2596.kt");
+    }
 }

libraries/stdlib/src/kotlin/Standard.kt

@@ -5,11 +5,6 @@ import java.util.Collection
 import java.util.HashSet
 import java.util.LinkedList
 
-/**
-Helper to make jet.Iterator usable in for
-*/
-public inline fun <T> Iterator<T>.iterator() : Iterator<T> = this
-
 /**
 Helper to make java.util.Iterator usable in for
 */