Make Map constructors return LinkedHashMap.

tests/corelib/map_from_iterables_test.dart

Index: tests/corelib/map_from_iterables_test.dart
diff --git a/tests/corelib/map_from_iterables_test.dart b/tests/corelib/map_from_iterables_test.dart
index 8c21e9f6b2ced4971c45672988ace394a07aa040..ca1793c2c556f7bd976527906ab6bc841d11f069 100644
--- a/tests/corelib/map_from_iterables_test.dart
+++ b/tests/corelib/map_from_iterables_test.dart
@@ -17,7 +17,7 @@ main() {
 void positiveTest() {
   var map = new Map.fromIterables([1, 2, 3], ["one", "two", "three"]);
   Expect.isTrue(map is Map);
-  Expect.isTrue(map is HashMap);
+  Expect.isTrue(map is LinkedHashMap);
 
   Expect.equals(3, map.length);
   Expect.equals(3, map.keys.length);
@@ -31,7 +31,7 @@ void positiveTest() {
 void emptyMapTest() {
   var map = new Map.fromIterables([], []);
   Expect.isTrue(map is Map);
-  Expect.isTrue(map is HashMap);
+  Expect.isTrue(map is LinkedHashMap);
 
   Expect.equals(0, map.length);
   Expect.equals(0, map.keys.length);
@@ -49,7 +49,7 @@ void fewerKeysIterableTest() {
 void equalElementsTest() {
   var map = new Map.fromIterables([1, 2, 2], ["one", "two", "three"]);
   Expect.isTrue(map is Map);
-  Expect.isTrue(map is HashMap);
+  Expect.isTrue(map is LinkedHashMap);
 
   Expect.equals(2, map.length);
   Expect.equals(2, map.keys.length);