[helmipradita]

Refs #7387

Description

In @std/expect equality matching (particularly under strictCheck: true for toStrictEqual):

1. Error constructors: a instanceof Error && b instanceof Error checked only a.message === b.message before strict constructor check, causing new Error("m") and new TypeError("m") to evaluate as equal.
2. ArrayBuffers & DataViews: Missing byte content checks meant buffers with different contents evaluated as equal because they share empty own keys.
3. Null-prototype objects: constructorsEqual treated !a.constructor && b.constructor === Object as equal; with strictCheck: true it now requires exact constructor equality (a.constructor === b.constructor), correctly rejecting Object.create(null) against {}.
4. Boxed primitives: Number, Boolean, Symbol, and BigInt wrapper objects now compare their underlying values via sameValueZero.
5. Keyed collections: Tracking unmatched entries with a Set in _equal.ts and _utils.ts (iterableEquality) prevents duplicate object entries in a from repeatedly matching the same entry in b.

[codecov]

Codecov Report

❌ Patch coverage is 91.76471% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 95.02%. Comparing base (f834d02) to head (f31ceb9).

Files with missing lines	Patch %	Lines
expect/_equal.ts	86.53%	2 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7393      +/-   ##
==========================================
- Coverage   95.04%   95.02%   -0.02%     
==========================================
  Files         619      618       -1     
  Lines       52012    51799     -213     
  Branches     9450     9424      -26     
==========================================
- Hits        49434    49224     -210     
+ Misses       2031     2022       -9     
- Partials      547      553       +6     

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