kfence: save freeing stack trace at calling time instead of freeing time

kfence: save freeing stack trace at calling time instead of freeing time

For kmem_cache with SLAB_TYPESAFE_BY_RCU, the freeing trace stack at
calling kmem_cache_free() is more useful. While the following stack is
meaningless and provides no help:
  freed by task 46 on cpu 0 at 656.840729s:
   rcu_do_batch+0x1ab/0x540
   nocb_cb_wait+0x8f/0x260
   rcu_nocb_cb_kthread+0x25/0x80
   kthread+0xd2/0x100
   ret_from_fork+0x34/0x50
   ret_from_fork_asm+0x1a/0x30

Link: https://lkml.kernel.org/r/20240812095517.2357-1-dtcccc@linux.alibaba.com
Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>