Port remaining Sky tests to the new world

sky/tests/lowlevel/unittest.dart

Index: sky/tests/lowlevel/unittest.dart
diff --git a/sky/tests/lowlevel/unittest.sky b/sky/tests/lowlevel/unittest.dart
similarity index 91%
rename from sky/tests/lowlevel/unittest.sky
rename to sky/tests/lowlevel/unittest.dart
index e32c2f0bc167c15f7c6b6ebaa4c08682a4bcdd47..5440f7b60d28b6a649454f9763e4b455f76e8f91 100644
--- a/sky/tests/lowlevel/unittest.sky
+++ b/sky/tests/lowlevel/unittest.dart
@@ -1,4 +1,3 @@
-<script>
 import "../resources/third_party/unittest/unittest.dart";
 import "../resources/unit.dart";
 
@@ -10,4 +9,3 @@ void main() {
     expect(x, equals(5));
   });
 }
-</script>>