Remove --multi-profiles flag from telemetry tests.

Bug should have been fixed in https://codereview.chromium.org/85703002

BUG=308224
NOTRY=True

Review URL: https://codereview.chromium.org/117133002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241875 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241875