[Reg 6.5.1->6.5.3] QJSEngine no longer converts new'ed JS object to QVariantMap

// test.js
function Person(firstName, lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
}

function greet(person) {
    console.log(`Hello, ${person.firstName} ${person.lastName}!`);
}

function testJohn() {
    let john = new Person("John", "Doe");
    greet(john);
    return john;
}

function testJane() {
    let jane = {
        firstName: "Jane",
        lastName: "Doe"
    };
    greet(jane);
    return jane;
}

// main.cpp
int main(int argc, char *argv[])
{
    QCoreApplication app(argc, argv);

    QFile script(":/test.js");
    script.open(QFile::ReadOnly|QFile::Text);

    QJSEngine engine;
    engine.installExtensions(QJSEngine::ConsoleExtension); // add console.log()
    engine.evaluate(script.readAll());

    qDebug() << engine.evaluate("testJane()").toVariant();
    qDebug() << engine.evaluate("testJohn()").toVariant();
}