Revert "sched_ext: Use shorter slice while bypassing"

This reverts commit 6f34d8d3.

Slice length is ignored while bypassing and tasks are switched on every tick
and thus the patch does not make any difference. The perceived difference
was from test noise.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: David Vernet <void@manifault.com>