Factories added to a set of Hydrogen classes.
Several old-style HXxx::New() replaced with New<HXxx>() and NewUncasted<HXxx>.
Several AddInstruction() calls following New::XXX() replaced with Add<XXX>().
AddLoadNamedField() method added to GraphBuilder.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/34523004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17318 ce2b1a6d-e550-0410-aec6-3dcde31c8c00