Handle non-JSObject heap objects using slow-path IC stub guarded by the map.

BUG=chromium:280632
R=mstarzinger@chromium.org

Review URL: https://chromiumcodereview.appspot.com/23691056

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16689 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
NumberUntagD is faster when untagging in a temp register

BUG=
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/23684056

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16690 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Reland "Clean up after r16292 (disable optimization for StringWrappers)."

BUG=
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/23619036

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16691 ce2b1a6d-e550-0410-aec6-3dcde31c8c00