Additional Profunctor tests covering lmap and rmap

[mikejcurry]

This adds additional tests for Profunctor which utilise the laws
infrastructure to exercise the derived lmap and rmap operations.

[codecov-io]

Current coverage is 81.46%

Merging #672 into master will increase coverage by +0.49% as of ff751d4

@@            master    #672   diff @@
======================================
  Files          159     159       
  Stmts         2123    2131     +8
  Branches        72      72       
  Methods          0       0       
======================================
+ Hit           1719    1736    +17
  Partial          0       0       
+ Missed         404     395     -9

Review entire Coverage Diff as of ff751d4

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[non]

👍 Looks great, thanks!

[ceedubs]

Excellent! 👍