Remove insertRange.

runtime/lib/array.dart

Index: runtime/lib/array.dart
diff --git a/runtime/lib/array.dart b/runtime/lib/array.dart
index ef49b7eec28dc6dfd1dfc274775e56095ad324e3..bd736aac4c03b9bed726fa8bbbf23c9f1628ee7d 100644
--- a/runtime/lib/array.dart
+++ b/runtime/lib/array.dart
@@ -86,12 +86,6 @@ class _ObjectArray<E> implements List<E> {
         "Cannot remove range of a non-extendable array");
   }
 
-  void insertRange(int start, int length, [E initialValue = null]) {
-    throw new UnsupportedError(
-        "Cannot insert range in a non-extendable array");
-  }
-
-
   List<E> sublist(int start, [int end]) {
     Arrays.indicesCheck(this, start, end);
     if (end == null) end = this.length;
@@ -318,11 +312,6 @@ class _ImmutableArray<E> implements List<E> {
         "Cannot remove range of an immutable array");
   }
 
-  void insertRange(int start, int length, [E initialValue = null]) {
-    throw new UnsupportedError(
-        "Cannot insert range in an immutable array");
-  }
-
   List<E> sublist(int start, [int end]) {
     Arrays.indicesCheck(this, start, end);
     if (end == null) end = this.length;