Revert change to strict property initialization checks

[ahejlsberg]

#29714 included a slight change to make strict property initialization checks more conservative. Turns out that isn't workable (it was inconsistent in its handling of any and broke the nightly build), so this PR reverts the change. The actual issue that #29714 fixed is unaffected by this.

[weswigham]

If we're reverting the bit that causes it, we should add a test case:

// @strict: true
// @target: es6
class Metadata {
    private _parent: Metadata | undefined;
    private _map: { [key: string]: any };

    constructor(parent?: Metadata) {
        this._parent = parent;
        this._map = Object.create(parent ? parent._map : null);
    }
}

so we know if it regresses before we get to publishing the nightly 😄