Check for read-only-ness when preparing for array sort.

R=verwaest@chromium.org
BUG=v8:2419

Review URL: https://chromiumcodereview.appspot.com/11759022

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13313 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Use enum instead of bool for force_generic (MISS / MISS_FORCE_GENERIC)

Review URL: https://chromiumcodereview.appspot.com/11737032

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13314 ce2b1a6d-e550-0410-aec6-3dcde31c8c00