Revert r12760 (JSON.stringify).

src/json.js

Index: src/json.js
diff --git a/src/json.js b/src/json.js
index 608cb7109d972f5981be6f51fefa17aab6ebc2ab..85224b0f053ffde051228ae9f66de947009db402 100644
--- a/src/json.js
+++ b/src/json.js
@@ -307,12 +307,10 @@ function BasicJSONSerialize(key, value, stack, builder) {
 
 function JSONStringify(value, replacer, space) {
   if (%_ArgumentsLength() == 1) {
-    var result = %BasicJSONStringify(value);
-    if (result != 0) return result;
     var builder = new InternalArray();
     BasicJSONSerialize('', value, new InternalArray(), builder);
     if (builder.length == 0) return;
-    result = %_FastAsciiArrayJoin(builder, "");
+    var result = %_FastAsciiArrayJoin(builder, "");
     if (!IS_UNDEFINED(result)) return result;
     return %StringBuilderConcat(builder, builder.length, "");
   }