benchmarks: timing_info: re-word thread abort actions

() The thread created to be used for timing measurement does not
   need to run, so use K_FOREVER instead of K_MSEC().
() Thread cancel is actually using k_thread_abort() so re-word it
   correctly to indicate it is aborting a non-running thread.
() The other k_thread_abort() is used on _current so re-word
   the item.

Relates to #25458

Signed-off-by: Daniel Leung <daniel.leung@intel.com>