3.20 branch: Fix HObjectAccess for loads from migrating prototypes

Cherrypick of V8 3.20 r17655.

BUG=chromium:305309
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/37253003

Bug: 11684308
Change-Id: Ie3f3835e7fc76f872d7b2dc77810ba3c96e12cc0
git-svn-id: http://v8.googlecode.com/svn/branches/3.20@17655 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
3 files changed