test_runner: simplify code and make it more consistent

[aduh95]

We can reuse the setOwnProperty helper; also I realized that deferred.resolve is sometimes used directly as a callback, or sometimes wrapped in an arrow function.

[nodejs-github-bot]

Review requested:

• @nodejs/test_runner

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.54%. Comparing base (0b6ae6d) to head (f4a66d2).
⚠️ Report is 14 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #60777      +/-   ##
==========================================
+ Coverage   88.04%   88.54%   +0.49%     
==========================================
  Files         703      703              
  Lines      208260   208249      -11     
  Branches    40068    40157      +89     
==========================================
+ Hits       183360   184389    +1029     
+ Misses      16840    15882     -958     
+ Partials     8060     7978      -82     

Files with missing lines	Coverage Δ
lib/internal/test_runner/test.js	97.34% <100.00%> (-0.02%)	⬇️

... and 104 files with indirect coverage changes

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[Hardanish-Singh]

LGTM!

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/70247/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/70249/

[nodejs-github-bot]

Landed in 5e6ac7e