Annonymous class in field initializer needs to treat surrounding class as under initialization

No error about clear NPE when calling function in annonymous class from constructor.
Discovered while discussing #903. Tested with v2.1.1.

class Foo {
  private final Object mBar;
  private final Runnable mRunnable =
        new Runnable() {
          @Override
          public void run() {
            // No problem, even though it NPEs.
            mBar.toString();
          }
        };

  public Foo() {
    mRunnable.run();
    mBar = "";
  }

  public static void main(String[] args) {
    new Foo();
  }
}