Integrate distribution-based comparison into `nvbench_compare.py`

[gevtushenko]

This issue can be closed by integrating results of #319 into nvbench_compare.py and one of:

• Re-use STATUS column and show INSUFFICIENT if data is not enough to make a decision, or print SAME and 0 / Nan in the %Diff columns regardless of the actual stdrel diff.
• If previous doesn't work, using extra command line flag to answer the questions