Mojo: Increase epsilon in tests.

Unfortunately, some things can't really be tested without small-ish
timeouts. Unfortunately our bots are slow/heavily loaded.

R=sky@chromium.org

Review URL: https://codereview.chromium.org/200353003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257119 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 257119