Avoid excessive memory usage during redundant phi elimination.

Basically, the work list for the fixed point iteration has been removed.

BUG=v8:2510

Review URL: https://codereview.chromium.org/12052075

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13505 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Replace store array length builtin with codestub.

Also includes some other minor cleanup to make Keyed related IC code
more uniform.

Review URL: https://chromiumcodereview.appspot.com/11896091

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13506 ce2b1a6d-e550-0410-aec6-3dcde31c8c00