Improve messages and static use for super/this-calls.

tests/compiler/dart2js/diagnose_ambiguous_test.dart

Index: tests/compiler/dart2js/diagnose_ambiguous_test.dart
diff --git a/tests/compiler/dart2js/diagnose_ambiguous_test.dart b/tests/compiler/dart2js/diagnose_ambiguous_test.dart
index 09e87060bd8d741e58ea9dc76ecb87fa01a83a52..2ae75ca2ca5eb9a68859c3b66ca7617d7c0fd303 100644
--- a/tests/compiler/dart2js/diagnose_ambiguous_test.dart
+++ b/tests/compiler/dart2js/diagnose_ambiguous_test.dart
@@ -23,11 +23,16 @@ void main() {
     });
     diagnostics.sort();
     var expected = [
-        "memory:exporter.dart:43:47:'hest' is defined here.:info",
-        "memory:library.dart:41:45:'hest' is defined here.:info",
-        "memory:main.dart:0:22:'hest' is imported here.:info",
-        "memory:main.dart:23:46:'hest' is imported here.:info",
-        "memory:main.dart:86:92:Duplicate import of 'hest'.:warning",
+        "MessageKind.AMBIGUOUS_LOCATION:"
+            "memory:exporter.dart:43:47:'hest' is defined here.:info",
+        "MessageKind.AMBIGUOUS_LOCATION:"
+            "memory:library.dart:41:45:'hest' is defined here.:info",
+        "MessageKind.DUPLICATE_IMPORT:"
+            "memory:main.dart:86:92:Duplicate import of 'hest'.:warning",
+        "MessageKind.IMPORTED_HERE:"
+            "memory:main.dart:0:22:'hest' is imported here.:info",
+        "MessageKind.IMPORTED_HERE:"
+            "memory:main.dart:23:46:'hest' is imported here.:info",
     ];
     Expect.listEquals(expected, diagnostics);
     Expect.isTrue(result.isSuccess);