feat: migrate from Tap to Jest

[cheton]

Marking the PR as being a work in progress

[codecov]

Codecov Report

Merging #220 (8fcbadc) into master (905bd96) will decrease coverage by 0.56%.
The diff coverage is 90.32%.

@@            Coverage Diff             @@
##           master     #220      +/-   ##
==========================================
- Coverage   91.22%   90.65%   -0.57%     
==========================================
  Files           6        6              
  Lines         581      535      -46     
==========================================
- Hits          530      485      -45     
+ Misses         51       50       -1     

Impacted Files	Coverage Δ
src/nodes-to-string.js	80.00% <77.14%> (-0.96%)	⬇️
src/parser.js	90.09% <89.97%> (-0.36%)	⬇️
src/index.js	98.07% <97.95%> (-0.32%)	⬇️
src/acorn-jsx-walk.js	100.00% <100.00%> (ø)
src/flatten-object-keys.js	100.00% <100.00%> (ø)
src/omit-empty-object.js	100.00% <100.00%> (ø)
... and 2 more

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