Move cats.tests.ListWrapper to cats-testkit

[ArturGajowy]

Fixes #2645

[codecov-io]

Codecov Report

Merging #2647 into master will increase coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2647      +/-   ##
==========================================
+ Coverage   95.12%   95.15%   +0.03%     
==========================================
  Files         363      364       +1     
  Lines        6704     6748      +44     
  Branches      305      289      -16     
==========================================
+ Hits         6377     6421      +44     
  Misses        327      327

Impacted Files	Coverage Δ
...estkit/src/main/scala/cats/tests/ListWrapper.scala	100% <ø> (ø)

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