Use symbol literals in the mirror tests. (Except for void, the empty string and setters.)

tests/lib/mirrors/method_mirror_properties_test.dart

Index: tests/lib/mirrors/method_mirror_properties_test.dart
diff --git a/tests/lib/mirrors/method_mirror_properties_test.dart b/tests/lib/mirrors/method_mirror_properties_test.dart
index c29c6f843f009ac29c84000d37336e8647f7191e..834871f399eaef743bc56b12dd84a09d287c2030 100644
--- a/tests/lib/mirrors/method_mirror_properties_test.dart
+++ b/tests/lib/mirrors/method_mirror_properties_test.dart
@@ -48,30 +48,30 @@ main() {
   checkKinds(closureMirror.function,
       [true, false, false, false, false]);
   var libraryMirror = reflectClass(C).owner;
-  checkKinds(libraryMirror.getters[const Symbol("topGetter")],
+  checkKinds(libraryMirror.getters[#topGetter],
       [true, false, true, false, false]);
   checkKinds(libraryMirror.setters[const Symbol("topSetter=")],
       [true, false, false, true, false]);
   var classMirror;
   classMirror = reflectClass(C);
-  checkKinds(classMirror.members[const Symbol("foo")],
+  checkKinds(classMirror.members[#foo],
       [true, false, false, false, false]);
-  checkKinds(classMirror.members[const Symbol("priv")],
+  checkKinds(classMirror.members[#priv],
       [false, false, true, false, false]);
   checkKinds(classMirror.members[const Symbol("priv=")],
       [false, false, false, true, false]);
-  checkKinds(classMirror.constructors[const Symbol("C")],
+  checkKinds(classMirror.constructors[#C],
       [false, false, false, false, true]);
-  checkKinds(classMirror.constructors[const Symbol("C.other")],
+  checkKinds(classMirror.constructors[#C.other],
       [false, false, false, false, true]);
-  checkKinds(classMirror.constructors[const Symbol("C.other2")],
+  checkKinds(classMirror.constructors[#C.other2],
       [false, false, false, false, true]);
   classMirror = reflectClass(AbstractC);
-  checkKinds(classMirror.constructors[const Symbol("AbstractC")],
+  checkKinds(classMirror.constructors[#AbstractC],
       [false, false, false, false, true]);
-  checkKinds(classMirror.members[const Symbol("bar")],
+  checkKinds(classMirror.members[#bar],
       [false, true, false, false, false]);
-  checkKinds(classMirror.members[const Symbol("priv")],
+  checkKinds(classMirror.members[#priv],
       [false, true, true, false, false]);
   checkKinds(classMirror.members[const Symbol("priv=")],
       [false, true, false, true, false]);