Tests extra updates

Fixes and updates to tests-extra.

added bug tests labels

assigned to @lpeltan and unassigned @dsalzman

added 10 commits

• 132abb05 - tests-extra: random DDNS updates -- don't count apex NS RRset removals as changes
• 7db67261 - tests-extra: make flush() wait for the file(s) update completion where it makes sense
• 15312384 - tests-extra: add wait as a parameter for ctl()
• 67270e7b - tests-extra: convert tests to use wait with ctl() where needed
• ccbabffd - tests-extra: dnssec/key_rollovers -- better robustness and xfr_diff testing even with Valgrind
• 3e6591fa - tests-extra: dnssec/ds_push -- make the test more stable (direct KSK rollover triggering)
• ad34d8e7 - tests-extra: enable zone verification even with Valgrind (zone_backup() can be made synchronous)
• fc92713e - tests-extra: modules/rrl -- more unified output style
• dfe5e3fe - tests-extra: modules/rrl -- make the test more stable under Valgrind
• afab164d - tests-extra: zone generator -- fix generation of the Retry value in SOA

Compare with previous version

removed bug label

merged

mentioned in commit 6dd931d6