Configuration:
- PDF.js version: 2.0.550

Steps to reproduce the problem:
1. Render document in SVG mode `renderMode="svg"`

What is the expected behavior? (add screenshot)
Rendering annotations same way as they rendered on canvas

What went wrong? (add screenshot)
```
Warning: Unimplemented operator beginAnnotations
Warning: Unimplemented operator endAnnotations
```
if (!this.pendingCleanup) {
      return false;
    }
    for (const { renderTasks, operatorList } of this._intentStates.values()) {
      if (renderTasks.size > 0 || !operatorList.lastChunk) {
        return false;
      }
    }
    this._intentStates.clear();
    this.objs.clear();
    this._annotationsPromise = null;
    this._jsActionsPromise = null;
    this._structTreePromise = null;
    if (resetStats && this._stats) {
      this._stats = new StatTimer();
    }
    this.pendingCleanup = false;
    return true;
  }
  /**
   * @private
   */
  _startRenderPage(transparency, intent) {