Update V8 to r3121 as required for WebKit update.

Change-Id: Ic53e0aef9a9eb9b71ee7d25a8aef61520bba899c
diff --git a/test/mjsunit/testcfg.py b/test/mjsunit/testcfg.py
index e3f3fcd..49064b1 100644
--- a/test/mjsunit/testcfg.py
+++ b/test/mjsunit/testcfg.py
@@ -114,7 +114,8 @@
     bugs = [current_path + ['bugs', t] for t in self.Ls(join(self.root, 'bugs'))]
     third_party = [current_path + ['third_party', t] for t in self.Ls(join(self.root, 'third_party'))]
     tools = [current_path + ['tools', t] for t in self.Ls(join(self.root, 'tools'))]
-    all_tests = mjsunit + regress + bugs + third_party + tools
+    compiler = [current_path + ['compiler', t] for t in self.Ls(join(self.root, 'compiler'))]
+    all_tests = mjsunit + regress + bugs + third_party + tools + compiler
     result = []
     for test in all_tests:
       if self.Contains(path, test):