Bad ES6 emit accessing named class-expression in its own static initializer

[jeffreymorlan]

let c = class NCE {
    static x = 1;
    static y = NCE.x * 2;
}

Output with --target ES6:

let c = (_a = class NCE {
    },
    _a.x = 1,
    _a.y = NCE.x * 2,
    _a);
var _a;

This fails at runtime as the class expression's name is out of scope.

(Inspired by #8363)