tests: Decrease the number of zones and switches for interconnection

When we run the tests with address sanitizers enabled
the interconnection test consumes a lot of memory,
around 5 GB (on my env) per permutation. To prevent
any OOM kills on Github CI reduce the number of
zones and transit switches to 3 as this lowers
the memory consumption to around 2 GB per permutation.

Signed-off-by: Ales Musil <amusil@redhat.com>
Signed-off-by: Mark Michelson <mmichels@redhat.com>
Acked-by: Mark Michelson <mmichels@redhat.com>

tests/ovn.at

@@ -22937,8 +22937,10 @@ OVN_FOR_EACH_NORTHD([
 AT_SETUP([interconnection])
 
 ovn_init_ic_db
-n_az=5
-n_ts=5
+# The number needs to stay relatively low due to high memory consumption
+# with address sanitizers enabled.
+n_az=3
+n_ts=3
 for i in `seq 1 $n_az`; do
     ovn_start az$i
 done