Fix error in compound assignment to keyed load by making platform-independent full compiler code platform dependent, add test of compound assignments.
Review URL: http://codereview.chromium.org/646009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3897 ce2b1a6d-e550-0410-aec6-3dcde31c8c00