Add a PRESUBMIT check that production code does not call test code

This is based on a regular expression matching anything in a namespace
ending in test, or a method containing the words ForTest, ForTesting,
for_test, or for_testing.

It is possible to blacklist entire directories or individual files.

BUG=none
LOG=n
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/589123002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24134 ce2b1a6d-e550-0410-aec6-3dcde31c8c00