Revert "selftests/sched_ext: fix build after renames in sched_ext API"

Revert "selftests/sched_ext: fix build after renames in sched_ext API"

This reverts commit fc20e87419e59d86f3bbcee2d4506bcd01c6450a which is
commit ef7009decc30eb2515a64253791d61b72229c119 upstream.

Commit "selftests/sched_ext: fix build after renames in sched_ext API”
was pulled into 6.12.y without the sched_ext API renames it depends on.
The prereqs can be found in
https://lore.kernel.org/lkml/20241110200308.103681-1-tj@kernel.org/
As a result, sched_ext selftests fail to compile.

Cc: stable@vger.kernel.org
Fixes: fc20e87419e59 ("selftests/sched_ext: fix build after renames in sched_ext API")
Signed-off-by: Libo Chen <libo.chen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>