Version 3.27.9.1 (merged r21405)

Comment out not yet used flags from BUILD.gn

R=machenbach@chromium.org
BUG=

Review URL: https://codereview.chromium.org/293063005

git-svn-id: https://v8.googlecode.com/svn/trunk@21406 ce2b1a6d-e550-0410-aec6-3dcde31c8c00