Output failed test case index in EOF validation tests

[gumb0]

Pulled out of #676

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (04247dd) 97.88% compared to head (fdad4c5) 97.88%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #820   +/-   ##
=======================================
  Coverage   97.88%   97.88%           
=======================================
  Files         113      113           
  Lines       10630    10631    +1     
=======================================
+ Hits        10405    10406    +1     
  Misses        225      225           

Flag	Coverage Δ
blockchaintests	59.88% <ø> (ø)
statetests	62.16% <ø> (ø)
statetests-silkpre	25.61% <0.00%> (ø)
unittests	95.87% <66.66%> (+<0.01%)	⬆️

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Files	Coverage Δ
test/unittests/eof_validation.cpp	85.71% <66.66%> (+2.38%)	⬆️