ANDROID: sched: Add replace_next_task_fair vendor hook in pick_next_task_fair

Add trace_android_rvh_replace_next_task_fair vendor hook in scheduler
to support OEM's need to override the selected task from pick_next_task_fair()
due to situations where important tasks are not picked in time.

Bug: 374011864
Change-Id: I55a0e7e794be77ba32c8adbff7b7eb2d914e4c52
Signed-off-by: Wanwei Jiang <wanwei.jiang@amlogic.com>
[jstultz: reworded commit message]
Signed-off-by: John Stultz <jstultz@google.com>