Do not overwrite builtin code names in heap profiler

Make sure builtin code objects get their builtin tags
first. Otherwise a particular JSFunction object could set
its custom name to a generic builtin.

LOG=N
R=ulan@chromium.org, yurys@chromium.org

Review URL: https://codereview.chromium.org/145973006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18926 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Make eager allocation site pretenuring decisions.

BUG=
R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/149393005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18927 ce2b1a6d-e550-0410-aec6-3dcde31c8c00