Add flag to skip pipe on select GMs

Confirmed with scroggo@ that these should not be run
with pipe.
Review URL: https://codereview.appspot.com/6405068

git-svn-id: http://skia.googlecode.com/svn/trunk@4698 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed