Change return type of get typeVariables and typeArguments in ClassMirror.

tests/lib/mirrors/typevariable_mirror_metadata_test.dart

Index: tests/lib/mirrors/typevariable_mirror_metadata_test.dart
diff --git a/tests/lib/mirrors/typevariable_mirror_metadata_test.dart b/tests/lib/mirrors/typevariable_mirror_metadata_test.dart
index 77f226b02bf6fcdb2577f4e8fe255501bf635426..9994988fc67c0bc7902c6b3b742d2e8314770890 100644
--- a/tests/lib/mirrors/typevariable_mirror_metadata_test.dart
+++ b/tests/lib/mirrors/typevariable_mirror_metadata_test.dart
@@ -32,17 +32,17 @@ typedef bool Predicate<@m1 @m2 G>(G a);
 main() {
   ClassMirror cm;
   cm = reflectClass(A);
-  checkMetadata(cm.typeVariables[const Symbol('S')], []);
-  checkMetadata(cm.typeVariables[const Symbol('T')], [m1, m2]);
+  checkMetadata(cm.typeVariables[0], []);
+  checkMetadata(cm.typeVariables[1], [m1, m2]);
   // Check for conflicts.
   checkMetadata(cm.methods[const Symbol('T')], [m3]);
 
   cm = reflectClass(B);
-  checkMetadata(cm.typeVariables[const Symbol('T')], [m3]);
+  checkMetadata(cm.typeVariables[0], [m3]);
   // Check for conflicts.
   checkMetadata(cm.members[const Symbol('T')], [m1, m2]);
 
   TypedefMirror tm = reflectClass(Predicate);
   FunctionTypeMirror ftm = tm.referent;
-  checkMetadata(ftm.typeVariables[const Symbol('G')], [m1, m2]);
+  checkMetadata(ftm.typeVariables[0], [m1, m2]);
 }