make collection traversals stack safe

[johnynek]

close #3517

This makes all the traversals of all collections stack safe.

It follows the approach of: typelevel/fs2#1957 but it is lazier (and maybe a bit slower because of that).

Cats has some tests that traversals on Applicatives that have lazy map2Eval instances that it won't trigger the function in those cases, so these laws require the traverse not only to have a certain result, but also invoke a function a known number of times.

I added tests before making each change and showed that the collection would fail a certain traversal (using Function0 as an example monad with poor stack safety).

[codecov-commenter]

Codecov Report

Merging #3521 into master will decrease coverage by 0.19%.
The diff coverage is 83.58%.

@@            Coverage Diff             @@
##           master    #3521      +/-   ##
==========================================
- Coverage   91.49%   91.30%   -0.20%     
==========================================
  Files         386      380       -6     
  Lines        8486     8288     -198     
  Branches      258      222      -36     
==========================================
- Hits         7764     7567     -197     
+ Misses        722      721       -1     

[LukaJCB]

This is really great, thanks @johnynek!