This provides more precise source to generated code mapping as variable loads can be handled using IC calls.

R=kmillikin@chromium.org

BUG=v8:1527
TEST=test/message/regress/regress-1527

Review URL: http://codereview.chromium.org//7327038

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8610 ce2b1a6d-e550-0410-aec6-3dcde31c8c00