Update perf expectations for nacl_helper sizes on Linux_x64

BUG=345710
NOTRY=true
TBR=hidehiko@chromium.org,mseaborn@chromium.org,joi@chromium.org

Review URL: https://codereview.chromium.org/175303002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252572 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252572