allequal(f, itr) and allunique(f, itr)

[mcabbott]

Adds JuliaLang/julia#47679

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (9e88843) 92.37% compared to head (295af03) 92.65%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #818      +/-   ##
==========================================
+ Coverage   92.37%   92.65%   +0.28%     
==========================================
  Files           2        2              
  Lines         341      354      +13     
==========================================
+ Hits          315      328      +13     
  Misses         26       26              

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[martinholters]

The @test_skips are a bit unfortunate, but the documentation in Base allows this ("The precise number of calls is regarded as an implementation detail."), so ok.

But this reminds me of #814. We would be better off if we had defined unexported Compat.allequal and Compat.allunique. Then we could just keep rolling our own here, regardless of Julia version.

[mcabbott]

Yea maybe. I'd need another coffee to think about what happens on the Julia versions where this package stops exporting allequal but Base doesn't yet provide allequal(f, itr). If this package had never exported it, that would indeed be simpler.