Upgrade V8 to 5.1.281.57  DO NOT MERGE

FPIIM-449

Change-Id: Id981b686b4d587ac31697662eb98bb34be42ad90
(cherry picked from commit 3b9bc31999c9787eb726ecdbfd5796bfdec32a18)
diff --git a/test/test262/archive.py b/test/test262/archive.py
index 8398e51..c265b32 100755
--- a/test/test262/archive.py
+++ b/test/test262/archive.py
@@ -8,10 +8,15 @@
 
 os.chdir(os.path.dirname(os.path.abspath(__file__)))
 
+# Workaround for slow grp and pwd calls.
+tarfile.grp = None
+tarfile.pwd = None
+
 def filter_git(tar_info):
   if tar_info.name.startswith(os.path.join('data', '.git')):
     return None
   else:
+    tar_info.uname = tar_info.gname = "test262"
     return tar_info
 
 with tarfile.open('data.tar', 'w') as tar: