Reland "Introduce intrinsics for double values in Javascript."

This relands r19704 with a fix to the test case.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/189823003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19723 ce2b1a6d-e550-0410-aec6-3dcde31c8c00