Property initializers capture the wrong 'arguments' value

[DanielRosenwasser]

When a variable named arguments is used in a property initializer, our emitted code refers to the wrong arguments.

Input

var arguments = 100;

class C {
    y = arguments;
    constructor() {
    }
}

Output

var arguments = 100;
var C = (function () {
    function C() {
        this.y = arguments;
    }
    return C;
})();

[mhegazy]

This looks like the instance side of #442.

[RyanCavanaugh]

All cool code is in strict mode now