[MERGE #3892 @boingoing] Top level event handlers have an implicit 'this' binding
[MERGE #3892 @boingoing] Top level event handlers have an implicit 'this' binding

Merge pull request #3892 from boingoing:ImplicitThisForEventHandler

mrkmarron/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,Microsoft/ChakraCore