added polyfill message
added polyfill message

Summary:Fixes https://github.com/facebook/relay/issues/690
I couldn't really find more es6 stuff other than what it checks (except for `Map` which got transpiled to `_Map` for some reason).
Not sure about tests.. Do we need a test for this and where should it go if so?
cc josephsavona
Closes https://github.com/facebook/relay/pull/1014

Reviewed By: yungsters

Differential Revision: D3142853

Pulled By: kassens

fb-gh-sync-id: 854402283af0ae529bb474ef5727589bf063af11
fbshipit-source-id: 854402283af0ae529bb474ef5727589bf063af11

cesarandreu/relay,facebook/relay,kassens/relay,dbslone/relay,facebook/relay,josephsavona/relay,xuorig/relay,voideanvalue/relay,atxwebs/relay,benjaminogles/relay,josephsavona/relay,cesarandreu/relay,chirag04/relay,kassens/relay,josephsavona/relay,xuorig/relay,atxwebs/relay,voideanvalue/relay,mroch/relay,facebook/relay,mroch/relay,voideanvalue/relay,mroch/relay,rosskevin/relay,chirag04/relay,iamchenxin/relay,yungsters/relay,kassens/relay,chentsulin/relay,voideanvalue/relay,iamchenxin/relay,chentsulin/relay,freiksenet/relay,facebook/relay,freiksenet/relay,wincent/relay,cpojer/relay,xuorig/relay,wincent/relay,kassens/relay,chirag04/relay,wincent/relay,zpao/relay,xuorig/relay,apalm/relay,yungsters/relay,chentsulin/relay,yungsters/relay,benjaminogles/relay,kassens/relay,kassens/relay,cpojer/relay,wincent/relay,atxwebs/relay,wincent/relay,apalm/relay,voideanvalue/relay,gabelevi/relay,cpojer/relay,facebook/relay,benjaminogles/relay,gabelevi/relay,freiksenet/relay,iamchenxin/relay,cesarandreu/relay,dbslone/relay,xuorig/relay,iamchenxin/relay,xuorig/relay,apalm/relay,rosskevin/relay,wincent/relay,facebook/relay,zpao/relay,atxwebs/relay,cpojer/relay,gabelevi/relay,zpao/relay,voideanvalue/relay