rules: add test_runner subsystem

[aduh95]

Refs: nodejs/node#42325

[codecov]

Codecov Report

Merging #96 (858e5f1) into main (4b63657) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main      #96   +/-   ##
=======================================
  Coverage   93.88%   93.88%           
=======================================
  Files          19       19           
  Lines         458      458           
=======================================
  Hits          430      430           
  Misses         28       28           

Impacted Files	Coverage Δ
lib/rules/subsystem.js	100.00% <ø> (ø)

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[Trott]

This might be obvious, but I think we should publish this immediately. We can always remove it if the test_runner module doesn't end landing, or update it if the name changes. I'd rather not have core-validate-commit be the thing that prevents easy landing of the PR.

[richardlau]

Published in core-validate-commit@3.16.0.