Make broken tests less noisy

[lgoettgens]

Resolves #231.

The tests that may print long lists of things now only do that in the case of a failure. If the test is supplied broken=true, only the number of instances is printed instead.

[codecov]

Codecov Report

Attention: Patch coverage is 63.63636% with 12 lines in your changes are missing coverage. Please review.

Project coverage is 75.06%. Comparing base (6f3067c) to head (e6d4ab0).

Files	Patch %	Lines
src/piracies.jl	16.66%	5 Missing ⚠️
src/exports.jl	66.66%	3 Missing ⚠️
src/ambiguities.jl	83.33%	2 Missing ⚠️
src/unbound_args.jl	66.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #272      +/-   ##
==========================================
- Coverage   75.46%   75.06%   -0.41%     
==========================================
  Files          11       11              
  Lines         750      762      +12     
==========================================
+ Hits          566      572       +6     
- Misses        184      190       +6     

Flag	Coverage Δ
unittests	75.06% <63.63%> (-0.41%)	⬇️

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[lgoettgens]

Is this how you imagined it @jishnub?

[jishnub]

Yes, thanks, this looks exactly like what I wanted