Disble FormStructureBrowserTest on Linux

FormStructureBrowserTest.DataDrivenHeuristics16 is failing on "Linux Tests"
http://build.chromium.org/p/chromium.linux/builders/Linux%20Tests/builds/7100

TBR=isherman@chromium.org
BUG=323093

Review URL: https://codereview.chromium.org/85213002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237033 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237033