Enabled JSON tests.

builtin_json.go

@@ -493,6 +493,7 @@ func (r *Runtime) initJSON() {
 	JSON := r.newBaseObject(r.global.ObjectPrototype, "JSON")
 	JSON._putProp("parse", r.newNativeFunc(r.builtinJSON_parse, nil, "parse", nil, 2), true, false, true)
 	JSON._putProp("stringify", r.newNativeFunc(r.builtinJSON_stringify, nil, "stringify", nil, 3), true, false, true)
+	JSON._putSym(symToStringTag, valueProp(asciiString(classJSON), false, false, true))
 
 	r.addToGlobal("JSON", JSON.val)
 }

object.go

@@ -25,6 +25,7 @@ const (
 	classError    = "Error"
 	classRegExp   = "RegExp"
 	classDate     = "Date"
+	classJSON     = "JSON"
 
 	classArrayIterator  = "Array Iterator"
 	classMapIterator    = "Map Iterator"

tc39_test.go

@@ -164,6 +164,7 @@ var (
 		"23.4",
 		"24.1",
 		"24.2",
+		"24.3",
 		"25.1.2",
 		"26.1",
 		"26.2",