lib: brand-check Navigator getters to throw ERR_INVALID_THIS

[3zrv]

Fixes: #63513

Add an explicit #field in this brand check to each getter so a proper ERR_INVALID_THIS is thrown, matching browser behavior. This also fixes language, which previously did not error at all on the prototype because it did not touch a private field.

[nodejs-github-bot]

Review requested:

• @nodejs/web-standards

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.32%. Comparing base (2cdea86) to head (a8d88e8).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #63601   +/-   ##
=======================================
  Coverage   90.32%   90.32%           
=======================================
  Files         730      730           
  Lines      234669   234680   +11     
  Branches    43946    43965   +19     
=======================================
+ Hits       211967   211985   +18     
  Misses      14417    14417           
+ Partials     8285     8278    -7     

Files with missing lines	Coverage Δ
lib/internal/navigator.js	99.40% <100.00%> (+0.03%)	⬆️

... and 27 files with indirect coverage changes

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[aduh95]

I don't think adding a check is worth it, I think the current behavior is fine actually, the spec requires a TypeError, we're throwing a TypeError (except for .language, indeed that's worth fixing). For reference, Chromium-based browsers throw TypeError: Illegal invocation

[LiviaMedeiros]

+1 on explicit ERR_INVALID_THIS over implicit private field access. Errors from private fields are misleading and not future-proof: it's too easy to break 'implicit throw' unintentionally (in fact, Navigator.prototype.language was initially introduced using private field, too).

[aduh95]

Errors from private fields are misleading and not future-proof: it's too easy to break 'implicit throw' unintentionally

It’s only true if that’s not covered by tests (which I would have expected WPT to cover, but I guess not, or at least not the subset we’re running)

[KhafraDev]

In undici we are lenient with errors too with the expectation that a reviewer would notice if a change similar to the one that changed .language was made.

Since it's not reasonable here, I think the change is fine. Regarding the WPTs, brand checks should be implemented the same across globals in most platforms so the assumption is that if you have it implemented properly in one spec, it's also implemented correctly in the thousands of over browser globals.

[KhafraDev]

Suggested change

	const getterNames = [
	'hardwareConcurrency',
	'locks',
	'language',
	'languages',
	'userAgent',
	'platform',
	];
	for (const name of getterNames) {
	for (const name of Object.keys(Navigator.prototype)) {