Add gn unit tests to the build on Linux.

R=dpranke@chromium.org, phajdan.jr@chromium.org

Review URL: https://codereview.chromium.org/357073002

git-svn-id: http://src.chromium.org/chrome/trunk/src/testing@285293 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
Don't run GN unit tests on Linux ChromiumOS.

Apparently this target isn't built there and running fails with a weird error.

TBR=phajdan.jr@chromium.org,,

Review URL: https://codereview.chromium.org/416153003

git-svn-id: http://src.chromium.org/chrome/trunk/src/testing@285332 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
Remove GN test from bots.

This is causing mysterious output failures on the bots

TBR=phajdan.jr

Review URL: https://codereview.chromium.org/412263004

git-svn-id: http://src.chromium.org/chrome/trunk/src/testing@285388 4ff67af0-8c30-449e-8e8b-ad334ec8d88c