Update V8 to r3431 as required by WebKit r51976.

Change-Id: I567392c3f8c0a0d5201a4249611ac4ccf468cd5b
diff --git a/test/mozilla/testcfg.py b/test/mozilla/testcfg.py
index 477b2b2..d1c1767 100644
--- a/test/mozilla/testcfg.py
+++ b/test/mozilla/testcfg.py
@@ -103,6 +103,7 @@
         for excluded in EXCLUDED:
           if excluded in dirs:
             dirs.remove(excluded)
+        dirs.sort()
         root_path = root[len(self.root):].split(os.path.sep)
         root_path = current_path + [x for x in root_path if x]
         framework = []
@@ -113,6 +114,7 @@
           if exists(script):
             framework.append(script)
         framework.reverse()
+        files.sort()
         for file in files:
           if (not file in FRAMEWORK) and file.endswith('.js'):
             full_path = root_path + [file[:-3]]