telemetry: Remove legacy trace results

R=nduca@chromium.org,tonyg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/178443003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253482 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253482