Set 'isSyntheticDefault' for default constructors.

pkg/front_end/testcases/inference/try_catch.dart.direct.expect

Index: pkg/front_end/testcases/inference/try_catch.dart.direct.expect
diff --git a/pkg/front_end/testcases/inference/try_catch.dart.direct.expect b/pkg/front_end/testcases/inference/try_catch.dart.direct.expect
index 7a73e4c491ad6cc6c9fdc01396fd75dd3aeccd9b..1fc62c6ecf6feec2e1603ce6bfe04a8a2c0266fb 100644
--- a/pkg/front_end/testcases/inference/try_catch.dart.direct.expect
+++ b/pkg/front_end/testcases/inference/try_catch.dart.direct.expect
@@ -3,17 +3,17 @@ import self as self;
 import "dart:core" as core;
 
 class C extends core::Object {
-  constructor •() → void
+  default constructor •() → void
     : super core::Object::•()
     ;
 }
 class D extends core::Object {
-  constructor •() → void
+  default constructor •() → void
     : super core::Object::•()
     ;
 }
 class E extends core::Object {
-  constructor •() → void
+  default constructor •() → void
     : super core::Object::•()
     ;
 }