more war on "sleep" in tests

more war on "sleep" in tests

Two more tests that sleep only to waste tick can be converted to use
test_tick and take expiry parameters relative to $test_tick.  The basic
idea is to replace "sleep 1" with "test_tick" to cause the "time" to pass.

These tests are interested in expiring things with "now" as the timestamp,
soo use a timestamp relative to $test_tick to give them more stability and
reproducibility.

Signed-off-by: Junio C Hamano <gitster@pobox.com>