Use List instead of Link in the type system.

sdk/lib/_internal/compiler/implementation/util/util.dart

Index: sdk/lib/_internal/compiler/implementation/util/util.dart
diff --git a/sdk/lib/_internal/compiler/implementation/util/util.dart b/sdk/lib/_internal/compiler/implementation/util/util.dart
index 8b195d6a6191439b361eace2c74ea557d1a603d3..ea90a2db1ccc83a9762059f225c1d1e67bf4fe7a 100644
--- a/sdk/lib/_internal/compiler/implementation/util/util.dart
+++ b/sdk/lib/_internal/compiler/implementation/util/util.dart
@@ -47,6 +47,16 @@ class SpannableAssertionFailure {
                        '${message != null ? ': $message' : ''}';
 }
 
+bool equalElements(List a, List b) {
+  if (a.length != b.length) return false;
+  for (int index = 0; index < a.length; index++) {
+    if (a[index] != b[index]) {
+      return false;
+    }
+  }
+  return true;
+}
+
 /**
  * File name prefix used to shorten the file name in stack traces printed by
  * [trace].