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/test/cctest/cctest_exe.isolate b/test/cctest/cctest_exe.isolate
new file mode 100644
index 0000000..da53278
--- /dev/null
+++ b/test/cctest/cctest_exe.isolate
@@ -0,0 +1,13 @@
+# Copyright 2016 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+{
+  'variables': {
+    'files': [
+      '<(PRODUCT_DIR)/cctest<(EXECUTABLE_SUFFIX)',
+    ],
+  },
+  'includes': [
+    '../../src/base.isolate',
+  ],
+}