Object [[Get]] does not inherit user-assigned Object.prototype properties through the prototype chain

[proggeramlug]

Surfaced while landing #4595 (JSON.parse reviver). General object-model gap, not reviver-specific.

A plain object's [[Get]] does not walk to Object.prototype for properties assigned there at runtime. Minimal repro:

(Object.prototype as any).foo = 99;
const o: any = { foo: 1 };
delete o.foo;
console.log(o.foo); // Node: 99 (inherited)   Perry: 1 / undefined

Node prints 99; Perry returns the stale own value (or undefined after delete) — the inherited Object.prototype.foo is never consulted.

Failing test262 (built-ins/JSON/parse/), which rely on re-reading an inherited value after the reviver deletes the own property:

• reviver-object-get-prop-from-prototype
• reviver-array-get-prop-from-prototype

The reviver walk now correctly does a real [[Get]] re-read per #4595; it's [[Get]]'s prototype-chain traversal for assigned Object.prototype members that's missing.

[andrewtdiz]

I am taking this as part of a focused object/array property-operation cut with #4657.

Scope: align ordinary [[Get]] prototype-chain reads for runtime-assigned Object.prototype properties, add parity coverage for inherited reads after deleting own JSON.parse reviver properties, and keep Proxy trap forwarding / JSON.parse source-context support out of this PR.

[andrewtdiz]

Implemented in #4665.

This patch makes JSON reviver holder re-reads fall back through Object.prototype after an own property is deleted, while preserving the original receiver for inherited accessors.

Validation run locally:

• npm exec --yes --package=node@26 -- node --experimental-strip-types test-parity/node-suite/globals/json-parse-reviver-internalize.ts
• cargo test -p perry-runtime json -j 2
• cargo test -p perry-runtime object -j 2 -- --test-threads=1
• cargo check -p perry-runtime -j 2
• cargo fmt --all -- --check
• git diff --check HEAD~1..HEAD
• ./scripts/check_file_size.sh

Focused Perry parity was attempted locally with single-job release builds, but the release build did not complete under machine-level release-build contention; no parity mismatch report was produced.