Revert "Revert "Upgrade to 5.0.71.48"" DO NOT MERGE

This reverts commit f2e3994fa5148cc3d9946666f0b0596290192b0e,
and updates the x64 makefile properly so it doesn't break that
build.

FPIIM-449

Change-Id: Ib83e35bfbae6af627451c926a9650ec57c045605
(cherry picked from commit 109988c7ccb6f3fd1a58574fa3dfb88beaef6632)
diff --git a/src/js/json.js b/src/js/json.js
index b8836ea..73d7802 100644
--- a/src/js/json.js
+++ b/src/js/json.js
@@ -187,7 +187,7 @@
 
 
 function JSONStringify(value, replacer, space) {
-  if (%_ArgumentsLength() == 1 && !IS_PROXY(value)) {
+  if (arguments.length === 1 && !IS_PROXY(value)) {
     return %BasicJSONStringify(value);
   }
   if (!IS_CALLABLE(replacer) && %is_arraylike(replacer)) {
@@ -234,6 +234,9 @@
   } else {
     gap = "";
   }
+  if (!IS_CALLABLE(replacer) && !property_list && !gap && !IS_PROXY(value)) {
+    return %BasicJSONStringify(value);
+  }
   return JSONSerialize('', {'': value}, replacer, new InternalArray(), "", gap);
 }