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/runtime/runtime-proxy.cc b/src/runtime/runtime-proxy.cc
index 3a521c6..7764d25 100644
--- a/src/runtime/runtime-proxy.cc
+++ b/src/runtime/runtime-proxy.cc
@@ -58,9 +58,8 @@
   ElementsAccessor* accessor = arg_array->GetElementsAccessor();
   {
     DisallowHeapAllocation no_gc;
-    FixedArrayBase* elements = arg_array->elements();
     for (int i = 0; i < arguments_length; i++) {
-      accessor->Set(elements, i, args[i + 1]);
+      accessor->Set(arg_array, i, args[i + 1]);
     }
   }
   // 8. Return Call(trap, handler, «target, thisArgument, argArray»).
@@ -119,9 +118,8 @@
   ElementsAccessor* accessor = arg_array->GetElementsAccessor();
   {
     DisallowHeapAllocation no_gc;
-    FixedArrayBase* elements = arg_array->elements();
     for (int i = 0; i < arguments_length; i++) {
-      accessor->Set(elements, i, args[i + 1]);
+      accessor->Set(arg_array, i, args[i + 1]);
     }
   }
   // 8. Let newObj be ? Call(trap, handler, «target, argArray, newTarget »).