Implement DeclarationMirror.location for all but ParameterMirrors.

tests/lib/mirrors/mirrors_reader_test.dart

Index: tests/lib/mirrors/mirrors_reader_test.dart
diff --git a/tests/lib/mirrors/mirrors_reader_test.dart b/tests/lib/mirrors/mirrors_reader_test.dart
index e66c5f0db869cec3ac5ef510aad7dc666e5f5712..5528701e01f8861ddcc7d75b1016bd688f4d53f8 100644
--- a/tests/lib/mirrors/mirrors_reader_test.dart
+++ b/tests/lib/mirrors/mirrors_reader_test.dart
@@ -33,6 +33,9 @@ class RuntimeMirrorsReader extends MirrorsReader {
   bool allowUnsupported(var receiver, String tag, UnsupportedError exception) {
     if (mirrorSystemType == '_LocalMirrorSystem') {
       // VM mirror system.
+      if (tag.endsWith('location')) {
+        return receiver is ParameterMirror;
+      }
     } else if (mirrorSystemType == 'JsMirrorSystem') {
       // Dart2js runtime mirror system.
       if (tag.endsWith('.metadata')) {
@@ -48,9 +51,6 @@ class RuntimeMirrorsReader extends MirrorsReader {
 
     if (mirrorSystemType == '_LocalMirrorSystem') {
       // VM mirror system.
-      if (receiver is DeclarationMirror && tag == 'location') {
-        return receiver is! MethodMirror;
-      }
     } else if (mirrorSystemType == 'JsMirrorSystem') {
       // Dart2js runtime mirror system.
       if (receiver is DeclarationMirror && tag == 'location') {