Clean up runtime type code
Clean up runtime type code

R=leafp@google.com

Review URL: https://codereview.chromium.org/1177233004.

ronlobo/dev_compiler,ochafik/dev_compiler,ronlobo/dev_compiler,ochafik/dev_compiler,ochafik/dev_compiler,ronlobo/dev_compiler,ronlobo/dev_compiler,ochafik/dev_compiler