Set 'isSyntheticDefault' for default constructors.

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

Index: pkg/front_end/testcases/inference/infer_field_override_multiple.dart.direct.expect
diff --git a/pkg/front_end/testcases/inference/infer_field_override_multiple.dart.direct.expect b/pkg/front_end/testcases/inference/infer_field_override_multiple.dart.direct.expect
index 27bcb1e46273cf980b8a641824911b3e4aa1acab..0edb4f1a3a2eaf896f343eacfea7d76a793658dc 100644
--- a/pkg/front_end/testcases/inference/infer_field_override_multiple.dart.direct.expect
+++ b/pkg/front_end/testcases/inference/infer_field_override_multiple.dart.direct.expect
@@ -3,50 +3,50 @@ import self as self;
 import "dart:core" as core;
 
 abstract class A extends core::Object {
-  constructor •() → void
+  default constructor •() → void
     : super core::Object::•()
     ;
   abstract get x() → core::int;
 }
 abstract class B extends core::Object {
-  constructor •() → void
+  default constructor •() → void
     : super core::Object::•()
     ;
   abstract get x() → core::int;
 }
 abstract class C extends core::Object {
-  constructor •() → void
+  default constructor •() → void
     : super core::Object::•()
     ;
   abstract get x() → core::num;
 }
 abstract class D extends core::Object {
-  constructor •() → void
+  default constructor •() → void
     : super core::Object::•()
     ;
   abstract get x() → core::double;
 }
 class E extends self::A implements self::B {
   field dynamic x = null;
-  constructor •() → void
+  default constructor •() → void
     : super self::A::•()
     ;
 }
 class F extends self::A implements self::C {
   field dynamic x = null;
-  constructor •() → void
+  default constructor •() → void
     : super self::A::•()
     ;
 }
 class G extends self::A implements self::D {
   field dynamic x = null;
-  constructor •() → void
+  default constructor •() → void
     : super self::A::•()
     ;
 }
 class H extends self::C implements self::D {
   field dynamic x = null;
-  constructor •() → void
+  default constructor •() → void
     : super self::C::•()
     ;
 }