Add N frames omitted in backtrace frames

[chenyukang]

Original from #108938 (comment)

#108938 is merged, an follow-up action is adding "N frames omitted" line for avoiding confusion.
Maybe something like:

   1: short_ice_remove_middle_frames::seven
   2: short_ice_remove_middle_frames::sixth
   3: short_ice_remove_middle_frames::fifth::{{closure}}
   4: short_ice_remove_middle_frames::second
      [ 2 frames omitted]
   5: short_ice_remove_middle_frames::first

Need to make an PR for backtrace-rs first.