[feat] Add display name to the failure statistics

[ekouts]

Closes #2465 .

I think it's better to print both names, but if you don't like it we can completely remove the unique name.

[codecov-commenter]

Codecov Report

Merging #2472 (fd29d81) into master (e4a7776) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2472   +/-   ##
=======================================
  Coverage   85.71%   85.71%           
=======================================
  Files          56       56           
  Lines       10529    10529           
=======================================
  Hits         9025     9025           
  Misses       1504     1504           

Impacted Files	Coverage Δ
reframe/frontend/statistics.py	96.00% <100.00%> (ø)

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