Merged r16566, r16471 into 3.20 branch.

Fix polymorphic INTERCEPTOR StoreICs on ARM/MIPS

Representation of interceptor / handler properties are tagged. Otherwise store ICs will never be initialized, due to lookup->CanHoldValue(value);

BUG=chromium:284998,chromium:256330
R=verwaest@chromium.org, ulan@chromium.org

Review URL: https://codereview.chromium.org/23480102

git-svn-id: https://v8.googlecode.com/svn/branches/3.20@16884 ce2b1a6d-e550-0410-aec6-3dcde31c8c00