lib: avoid event override by assignment

[erights]

See #43907

[ljharb]

With this last comment, and with some tests (that install an inherited setter and verify it's not called, and then remove the setter, presumably) this PR LGTM

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.12%. Comparing base (59a763e) to head (fae8feb).
Report is 270 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #58315      +/-   ##
==========================================
- Coverage   90.22%   90.12%   -0.10%     
==========================================
  Files         633      639       +6     
  Lines      186836   188228    +1392     
  Branches    36678    36911     +233     
==========================================
+ Hits       168568   169640    +1072     
- Misses      11073    11320     +247     
- Partials     7195     7268      +73     

Files with missing lines	Coverage Δ
lib/events.js	99.83% <100.00%> (+0.08%)	⬆️

... and 170 files with indirect coverage changes

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