* factor the class heritage workaround so it's out of the way & easier to remove later.
* always emit type parameters in the AST, and pass the flag to the printer to skip printing them.
* cleanup an unnecessary sync* method for closure field decls.
* also, reformats. I think I forgot to do that in previous CL.
R=vsm@google.com
Review URL: https://codereview.chromium.org/1767803002 .