[turbofan] Refactor code generation for calls.

R=jarin@chromium.org
TEST=cctest

Review URL: https://codereview.chromium.org/508863002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23429 ce2b1a6d-e550-0410-aec6-3dcde31c8c00