Add a test of .throw called on new-born generators.
Add a test of .throw called on new-born generators.

rafaelstz/regenerator,sebmck/regenerator,RReverser/js-goto-transpiler,kittens/regenerator,jlongster/unwinder,RReverser/js-goto-transpiler,juliocanares/regenerator,kittens/regenerator,liviuignat/regenerator,facebook/regenerator,jlongster/unwinder,sebmck/regenerator,liviuignat/regenerator,Jericho25/regenerator,juliocanares/regenerator,jlongster/transmogrifier,facebook/regenerator,rafaelstz/regenerator,facebook/regenerator,jlongster/unwinder,jlongster/transmogrifier,Jericho25/regenerator