Roll kernel to latest and add baseline test.

pkg/compiler/lib/src/elements/elements.dart

Index: pkg/compiler/lib/src/elements/elements.dart
diff --git a/pkg/compiler/lib/src/elements/elements.dart b/pkg/compiler/lib/src/elements/elements.dart
index 534aad023395df25b2303618c6681812d6287a0c..29e2396e84a6db5c33f0d4844f0e78e8423622e4 100644
--- a/pkg/compiler/lib/src/elements/elements.dart
+++ b/pkg/compiler/lib/src/elements/elements.dart
@@ -1378,6 +1378,9 @@ abstract class ConstructorElement extends FunctionElement
   /// is `C.c`.
   ConstructorElement get definingConstructor;
 
+  /// Returns `true` if this constructor is an implicit default constructor.
+  bool get isDefaultConstructor;
+
   /// The constant constructor defining the binding of fields if `const`,
   /// `null` otherwise.
   ConstantConstructor get constantConstructor;