[json] replace remaining json.js code with C++ builtins.

test/mjsunit/debug-script.js

Index: test/mjsunit/debug-script.js
diff --git a/test/mjsunit/debug-script.js b/test/mjsunit/debug-script.js
index 539641508705ecb63a4398f87493bcf657a53b9e..3bedb74a35e29002359280e30ec0d76c4f03ffb0 100644
--- a/test/mjsunit/debug-script.js
+++ b/test/mjsunit/debug-script.js
@@ -84,11 +84,6 @@ var math_script = Debug.findScript('native math.js');
 assertEquals('native math.js', math_script.name);
 assertEquals(Debug.ScriptType.Native, math_script.type);
 
-// Test a builtins delay loaded script.
-var date_delay_script = Debug.findScript('native json.js');
-assertEquals('native json.js', date_delay_script.name);
-assertEquals(Debug.ScriptType.Native, date_delay_script.type);
-
 // Test a debugger script.
 var debug_delay_script = Debug.findScript('native debug.js');
 assertEquals('native debug.js', debug_delay_script.name);