Replace static blocks with private static field initializers

[davidtaylorhq]

Private static field initializers offer the same timing as class static blocks, while offering better browser support. For example, private static field initializers are supported on Safari >= 14.5 while static blocks are only supported in Safari >= 16.4.

Given this input:

class MyClass {
  @myDecorator
  decoratedField = 'field value';

  @myDecorator
  decoratedMethod() {
    return 'method response';
  }
}

This commit changes the output from:

class MyClass {
  static {
    dt7948.g(this.prototype, "decoratedField", [myDecorator], function () {
      return 'field value';
    });
  }
  #decoratedField = (dt7948.i(this, "decoratedField"), void 0);
  decoratedMethod() {
    return 'method response';
  }
  static {
    dt7948.n(this.prototype, "decoratedMethod", [myDecorator]);
  }
}

to this:

class MyClass {
  static #decoratedField = (dt7948.g(this.prototype, "decoratedField", [myDecorator], function () {
    return 'field value';
  }), void 0);
  #decoratedField_ = (dt7948.i(this, "decoratedField"), void 0);
  decoratedMethod() {
    return 'method response2';
  }
  static #decoratedMethod = (dt7948.n(this.prototype, "decoratedMethod", [myDecorator]), void 0);
}

Resolves #3

[davidtaylorhq]

The current implementation of unusedPrivateNameLike() means that a field named decoratedField will result in two private fields: #decoratedField and static #decoratedField_.

I think it would be beneficial to make the names more human-friendly like this:

static #_decorate_decoratedField = (...);
#_deferred_decorate_decoratedField = (...);

and for methods, something like:

someMethod(){}
static #_decorate_someMethod = (...);

If adding those prefixes would be welcome, let me know and I can either push it here or make a followup PR.

[davidtaylorhq]

@ef4 I've introduced a statickBlock: "native" | "field" feature flag here (defaults to 'native'). Please let me know if there's anything else I can do to help get this across the finish line.