BACKPORT: sched/fair: Do not try to migrate delayed dequeue task

Migrating a delayed dequeued task doesn't help in balancing the number
of runnable tasks in the system.

Bug: 438500731
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/20241202174606.4074512-11-vincent.guittot@linaro.org


[Trivial conflict in fair.c::can_migrate_task() comment due to new
addition of proxy execution condition that doesn't exist upstream]
(cherry picked from commit 61b82dfb)
Signed-off-by: Qais Yousef <qyousef@google.com>
Change-Id: I5fbd0a4d875288c02c7daf1d44e0efb8215c25cb