Generalized Call macro instruction to handle AST IDs, too, making things more
similar to the Intel assemblers. Removed unused methods. Minor signature
cleanup. Simplified assertions.
Review URL: http://codereview.chromium.org/7284029

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8482 ce2b1a6d-e550-0410-aec6-3dcde31c8c00