If dots are not escaped in the "1.2.3.4" regular expressions used for
checking whether IP address 1.2.3.4 is present in the tested resolver's
answers, a COOKIE that matches such a regular expression will trigger a
false positive for the "resolver" system test.  Properly escape dots in
the aforementioned regular expressions to prevent that from happening.

(cherry picked from commit 70ae48e5)