Fix kasp timing issue on Windows

This fixes another intermittent failure in the kasp system test. It does not happen often, except for in the Windows platform tests where it takes a long time to run the tests.

There is a 'rndc reconfig' in the kasp system test which triggers a new rekey event. The next key event is based on the time that the new rekey event is started. However, the checks in the kasp system test calculate the next key event on the start of the test. If the 'rndc reconfig' occurs much later than when the test is started, the 'check_next_key_event' checks will fail.

Fix by calculating the time passed since the start of the test and when 'rndc reconfig' happens. Substract this time from the calculated next key event.

This only needs to be done on zones where the keymgr needs to wait for a period of time (for example for keys to become OMNIPRESENT, or HIDDEN). This is on step 2 and step 5 of the algorithm rollover. In step 2 there is a waiting period before the DNSKEY is OMNIPRESENT, In step 5 there is a waiting period before the DNSKEY is HIDDEN.

In step 1 new keys are created, in step 3 and 4 key states just entered OMNIPRESENT, and in step 6 we no longer care because the key lifetime is unlimited and we default to checking once per hour.

Regardless of our indifference about the next key event after step 6, change some of the key timings in the setup script to better reflect reality: DNSKEY is in HIDDEN after step 5, DS times have changed when the new DS became active.

Closes #1669 (closed)