These tests reduce the server lock wait timeout which can increase
flakiness on loaded machines. Since this is merely an optimization,
eliminate them in favour of reliability.
Ref: #11328
These tests are run in SLOWDOWN mode which adds a 10 msec delay after
each character output, which means it takes at least 1.6 seconds (and
320 kernel calls) just to get through the long welcome banner. On an
overloaded system, this can end up taking much more than 1.6 seconds,
and even more than the 7 or 16 second curl timeout that the tests rely
on, causing them to fail. Reducing the size of the welcome banner drops
the total number of characters sent before the transfer starts by more
than half, which reduces the opportunity for test-breaking slowdowns by
the same amount.
Ref: #11328
