Mojo: re-organize public tests

Move sample service test to be with the rest of the bindings tests, and change it to not echo output by default.

R=viettrungluu@chromium.org

Review URL: https://codereview.chromium.org/134823005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244437 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244437