[9.18] Increase server start timeout for system tests
This commit increases server start timeout from 60 to 90 seconds in order to avoid system test failures on some platforms due to inability to initialise TLS contexts in time.
(cherry picked from commit 705f0d1e)
v9_18
and v9_18_sub
branches are the only maintained branches where system:gcc:bullseye:amd64cross32
fails to start the ns1
server. It failed to start 12 times in the last two months.
Backport of MR !6356 (merged)
Closes #3269 (closed)