Convert CONSTANT_FUNCTION to CONSTANT

R=yangguo@chromium.org

Review URL: https://chromiumcodereview.appspot.com/19485008

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15858 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Add --trace-hydrogen-stubs flag (default = false).

BUG=
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/20084003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15859 ce2b1a6d-e550-0410-aec6-3dcde31c8c00