Reapply "This change makes it easier to put type parameters on JavaScript Arrays."

tests/corelib/iterable_to_list_test.dart

Index: tests/corelib/iterable_to_list_test.dart
diff --git a/tests/corelib/iterable_to_list_test.dart b/tests/corelib/iterable_to_list_test.dart
index 6a5c454017c9e81827a54832ec56ebf5ff439ba8..3ee443a0a7895a57d03ca1e4b8c23490cadbfd7b 100644
--- a/tests/corelib/iterable_to_list_test.dart
+++ b/tests/corelib/iterable_to_list_test.dart
@@ -4,6 +4,12 @@
 
 import "package:expect/expect.dart";
 
+dynamicCheck(input, {isInt, isString}) {
+  var copy = input.toList();
+  Expect.isTrue(isInt == copy is List<int>);
+  Expect.isTrue(isString == copy is List<String>);
+}
+
 main() {
   List<int> list1 = <int>[1, 2, 3];
   List<int> list2 = const <int>[4, 5];
@@ -23,18 +29,21 @@ main() {
   Expect.isTrue(listCopy is List<int>);
   Expect.isFalse(listCopy is List<String>);
   Expect.isFalse(identical(list1, listCopy));
+  dynamicCheck(list1, isInt: true, isString: false);
 
   listCopy = list2.toList();
   Expect.listEquals(list2, listCopy);
   Expect.isTrue(listCopy is List<int>);
   Expect.isFalse(listCopy is List<String>);
   Expect.isFalse(identical(list2, listCopy));
+  dynamicCheck(list2, isInt: true, isString: false);
 
   listCopy = list3.toList();
   Expect.listEquals(list3, listCopy);
   Expect.isTrue(listCopy is List<String>);
   Expect.isFalse(listCopy is List<int>);
   Expect.isFalse(identical(list3, listCopy));
+  dynamicCheck(list3, isInt: false, isString: true);
 
   listCopy = set1.toList();
   Expect.equals(3, listCopy.length);
@@ -43,6 +52,7 @@ main() {
   Expect.isTrue(listCopy.contains(13));
   Expect.isTrue(listCopy is List<int>);
   Expect.isFalse(listCopy is List<String>);
+  dynamicCheck(set1, isInt: true, isString: false);
 
   listCopy = set2.toList();
   Expect.equals(3, listCopy.length);
@@ -51,9 +61,11 @@ main() {
   Expect.isTrue(listCopy.contains("toto"));
   Expect.isTrue(listCopy is List<String>);
   Expect.isFalse(listCopy is List<int>);
+  dynamicCheck(set2, isInt: false, isString: true);
 
   listCopy = set3.toList();
   Expect.isTrue(listCopy.isEmpty);
   Expect.isTrue(listCopy is List<int>);
   Expect.isTrue(listCopy is List<String>);
+  dynamicCheck(set3, isInt: true, isString: true);
 }