Add a second fuzzer for pipe equivalency

[MichaelChirico]

Part of #2191 -- continuing #2818 (which is included here & against which this is based, for now) with a demonstration of a second fuzzing rule. Also progress on #2737.

One worry is that eventually we'll get so many # nofuzz rules as to start creating false negatives, but I think we can worry about that more later -- our suite is quite large.

This fuzzer did not expose any issues with our linters (yay!)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.64%. Comparing base (523c218) to head (fe88c59).

Additional details and impacted files

@@           Coverage Diff           @@
##             fuzz    #2819   +/-   ##
=======================================
  Coverage   99.64%   99.64%           
=======================================
  Files         126      126           
  Lines        6961     6961           
=======================================
  Hits         6936     6936           
  Misses         25       25           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.