Use 'static {}' for static fields when available and useDefineForClassFields is false

[rbuckton]

This changes the emit for static field initializers to use static {} blocks when the target is ES2022+ and useDefineForClassFields is false. This allows us to preserve execution order for static fields, and keep static field assignments inside of the class body (granting them privileged access to private names).

This also correctly emits private static field initializers regardless of the useDefineForClassFields setting (since private fields use neither Set nor Define semantics).

For example:

// source
class C {
  static #x = 0;
  static y = this.#x;
  static [f()] = this.y;
}

// output
var _a;
class C {
  static { _a = f(); }
  static #x = 0;
  static { this.y = this.#x; }
  static { this[_a] = this.y; }
}

Fixes #45574

[sandersn]

This is a weird combination of flags, but it's one I might use if I were writing a lot of classes. Not sure if that makes it more or less likely to be widely used.