Stabilize cacheclean system test
Closes#67
See merge request isc-projects/bind9!43
(cherry picked from commit 643c8c27ff)
01de79b3 Assign an index to each check in the cacheclean system test
aeea1faf Do not overwrite cache dumps
2bbff06d Wait until a cache dump completes instead of waiting for a fixed amount of time
ca1049b2 Improve the way cache contents are searched for "ns.flushtest.example"
ea29bec179