Make LCodeGen::RegisterDependentCodeForEmbeddedMaps platform independent.

BUG=
R=hpayer@chromium.org

Review URL: https://chromiumcodereview.appspot.com/99053002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18231 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Mock out date call in push-to-trunk script for testability.

TEST=python -m unittest test_scripts.ScriptTest.testPrepareChangeLog
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/98173003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18232 ce2b1a6d-e550-0410-aec6-3dcde31c8c00