Use expect instead of unittest for json_lib_test.

pkg/dev_compiler/lib/src/compiler/code_generator.dart

Index: pkg/dev_compiler/lib/src/compiler/code_generator.dart
diff --git a/pkg/dev_compiler/lib/src/compiler/code_generator.dart b/pkg/dev_compiler/lib/src/compiler/code_generator.dart
index 456e8e345c5fae122d444cf393ace275029f5095..9cbc9ec0944963f19f5db971f50c5027fa1cbfb1 100644
--- a/pkg/dev_compiler/lib/src/compiler/code_generator.dart
+++ b/pkg/dev_compiler/lib/src/compiler/code_generator.dart
@@ -3890,7 +3890,9 @@ class CodeGenerator extends GeneralizingAstVisitor
       }
       var args = _visit(argumentList) as List<JS.Expression>;
       // Native factory constructors are JS constructors - use new here.
-      return isFactory && !isNative ? new JS.Call(ctor, args) : new JS.New(ctor, args);
+      return isFactory && !isNative
+          ? new JS.Call(ctor, args)
+          : new JS.New(ctor, args);
     }
 
     if (element != null && _isObjectLiteral(element.enclosingElement)) {