[MERGE #987] flush print/WScript.Echo output
[MERGE #987] flush print/WScript.Echo output

Merge pull request #987 from jianchun:flush
Flush stdout after print/WScript.Echo calls (don't know why we didn't have
one already). On Linux we found different stdout/stderr output order when
redirecting/piping output in python script.

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