sched_ext: Update selftests to drop ops.cpu_acquire/release()

sched_ext: Update selftests to drop ops.cpu_acquire/release()

ops.cpu_acquire/release() are deprecated by commit a3f5d4822253
("sched_ext: Allow scx_bpf_reenqueue_local() to be called from
anywhere") in favor of handling CPU preemption via the sched_switch
tracepoint.

In the maximal selftest, replace the cpu_acquire/release stubs with a
minimal sched_switch TP program. Attach all non-struct_ops programs
(including the new TP) via maximal__attach() after disabling auto-attach
for the maximal_ops struct_ops map, which is managed manually in run().

Apply the same fix to reload_loop, which also uses the maximal skeleton.

Signed-off-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>