Add generations to the compilation cache for eval and regexp. The number of generations for these are set to two.

BUG=none
TEST=none
Review URL: http://codereview.chromium.org/140056

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2233 ce2b1a6d-e550-0410-aec6-3dcde31c8c00