Enable whole program optimization for WIN64 to make build-bot green.
Enable whole program optimization for WIN64 to make build-bot green.

R=jkummerow@chromium.org
BUG=v8:2207

Review URL: https://chromiumcodereview.appspot.com/10636055

git-svn-id: b158db1e4b4ab85d4c9e510fdef4b1e8c614b15b@11933 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh