selftests/livepatch: Add selftests for "replace" sysfs attribute

Add selftests for both atomic replace and non atomic replace
livepatches. The result is as follows,

  TEST: sysfs test ... ok
  TEST: sysfs test object/patched ... ok
  TEST: sysfs test replace enabled ... ok
  TEST: sysfs test replace disabled ... ok

Suggested-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Tested-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/20240625151123.2750-3-laoar.shao@gmail.com


Signed-off-by: Petr Mladek <pmladek@suse.com>