playground: hit golang.org/compile endpoint instead of play.golang.org

Not sure why this was originally going via the playground. It needn't.

Change-Id: I40b5886a56ba4b941ff74f4bc325625412d7eaff
Reviewed-on: https://go-review.googlesource.com/22497
Reviewed-by: Andrew Gerrand <adg@golang.org>
1 file changed