Shorter sparse AD tests

[gdalle]

DIT source

• Reduce the number of sparse (banded) scenarios introduced in Add more sparse AD test scenarios #578 so that CI finishes within 1h. The issue is probably AutoReverseFromPrimitive(AutoForwardDiff()), whose pullbacks are by definition inefficient.

DI and DIT tests

• Make file test sets verbose so we can know what took how long inside each

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 90.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 97.57%. Comparing base (43bb14a) to head (02216a5).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
DifferentiationInterface/test/runtests.jl	50.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #579   +/-   ##
=======================================
  Coverage   97.56%   97.57%           
=======================================
  Files         110      110           
  Lines        5226     5227    +1     
=======================================
+ Hits         5099     5100    +1     
  Misses        127      127           

Flag	Coverage Δ
DI	98.59% <50.00%> (ø)
DIT	95.64% <100.00%> (+<0.01%)	⬆️

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