Set 'isSyntheticDefault' for default constructors.

pkg/front_end/testcases/inference/infer_assign_to_property_super.dart.outline.expect

Index: pkg/front_end/testcases/inference/infer_assign_to_property_super.dart.outline.expect
diff --git a/pkg/front_end/testcases/inference/infer_assign_to_property_super.dart.outline.expect b/pkg/front_end/testcases/inference/infer_assign_to_property_super.dart.outline.expect
index 985e4dacf9e6b7467a2b64e07ce2d2b03f28bb89..1337d5613d63317de223f187f70cc4be2a0d7582 100644
--- a/pkg/front_end/testcases/inference/infer_assign_to_property_super.dart.outline.expect
+++ b/pkg/front_end/testcases/inference/infer_assign_to_property_super.dart.outline.expect
@@ -3,11 +3,11 @@ import self as self;
 import "dart:core" as core;
 
 class A extends core::Object {
-  constructor •() → void
+  default constructor •() → void
     ;
 }
 class B extends self::A {
-  constructor •() → void
+  default constructor •() → void
     ;
   operator +(self::C v) → self::A
     ;
@@ -19,16 +19,16 @@ class B extends self::A {
     ;
 }
 class C extends self::B {
-  constructor •() → void
+  default constructor •() → void
     ;
 }
 class Base extends core::Object {
   field self::B member;
-  constructor •() → void
+  default constructor •() → void
     ;
 }
 class Test extends self::Base {
-  constructor •() → void
+  default constructor •() → void
     ;
   method test() → void
     ;