Add helper script that registers local NM hosts on user level.

The script is useful for testing locally built NM hosts
without building the whole package.

R=lambroslambrou@chromium.org

Review URL: https://codereview.chromium.org/168603005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252713 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252713