test_gap_object_methods: frozen / sealed / non-extensible writes don't throw in strict mode

[proggeramlug]

Summary

test-files/test_gap_object_methods.ts baseline parity failure (one of the 3 in CLAUDE.md). Filing as a tracked issue.

Symptom

Specifically: mutations against frozen / sealed / non-extensible objects, and writes to defineProperty(... writable:false) properties, don't throw in strict mode. Node prints the "threw" branch; perry's try/catch never fires, so 5 lines of expected output are missing:

< defineProperty write threw (strict mode)
< freeze write threw
< freeze add threw
< sealed add threw
< preventExtensions add threw

Perry silently allows the mutation (the read-back values are also not what Node shows, since the writes succeed).

Reproducer

"use strict";
const obj: Record<string, unknown> = {};
Object.defineProperty(obj, "readOnly", {
    value: 42,
    writable: false,
    enumerable: true,
    configurable: false,
});

try {
    (obj as any).readOnly = 100;  // should throw in strict
    console.log("did NOT throw");
} catch {
    console.log("threw — correct");
}

Node strict-mode path → threw — correct. Perry → did NOT throw.

Same shape for Object.freeze(obj); obj.x = 1, Object.seal(obj); obj.added = 2, Object.preventExtensions(obj); obj.added = 3.

Probable scope

The runtime's js_object_set_field_by_name path (and its numeric-index sibling) either has no frozen/sealed/preventExtensions check, or has the check but doesn't throw — silently no-ops. CLAUDE.md mentions a defineProperty issue at #450 (defineProperty accessor this) but that's a different gap. This one's about strict-mode-throw semantics.

Environment

• Perry 0.5.710
• macOS arm64 / 26.4
• Surfaced by scripts/release_sweep.sh tier 2 (parity, baseline failure)

[proggeramlug]

Fixed in v0.5.713 (commit cc6647c). See changelog for details.