XS incorrectly accepts assignment/binding patterns `{...rest,}`

[gibson042]

Environment: XS 17.9.1, slot 32 bytes, ID 4 bytes

Description
Object destructuring does not conform with the ECMAScript specification.

Steps to Reproduce

let rest;
for({ ...rest, } of []);
print("EVALUATED");

Actual behavior

EVALUATED

Expected behavior
SyntaxError

Other information
spec link: Destructuring Assignment
test262 pull request: tc39/test262#5102

[phoddie]

Thank you for the report!