Don't call dinvoke on Object methods

test/dart_codegen/expect/collection/hash_map.dart

 part of dart.collection;
  bool _defaultEquals(a, b) => a == b;
- int _defaultHashCode(a) => DEVC$RT.cast(a.hashCode, dynamic, int, "DynamicCast", """line 10, column 28 of dart:collection/hash_map.dart: """, a.hashCode is int, true);
+ int _defaultHashCode(a) => a.hashCode;
  typedef bool _Equality<K>(K a, K b);
  typedef int _Hasher<K>(K object);
  abstract class HashMap<K, V> implements Map<K, V> {external factory HashMap({
   bool equals(K key1, K key2), int hashCode(K key), bool isValidKey(potentialKey)}
 );
  external factory HashMap.identity();
  factory HashMap.from(Map other) {
   HashMap<K, V> result = new HashMap<K, V>();
    other.forEach((k, v) {
     result[k] = DEVC$RT.cast(v, dynamic, V, "CompositeCast", """line 87, column 40 of dart:collection/hash_map.dart: """, v is V, false);
     }
   );
    return result;
   }
  factory HashMap.fromIterable(Iterable iterable, {
   K key(element), V value(element)}
 ) {
   HashMap<K, V> map = new HashMap<K, V>();
    Maps._fillMapWithMappedIterable(map, iterable, key, value);
    return map;
   }
  factory HashMap.fromIterables(Iterable<K> keys, Iterable<V> values) {
   HashMap<K, V> map = new HashMap<K, V>();
    Maps._fillMapWithIterables(map, keys, values);
    return map;
   }
 }