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
```
while (this.stateStack.length || this.current.activeSMask !== null) {
        this.restore();
      }
      this.ctx.restore();
      if (this.transparentCanvas) {
        this.ctx = this.compositeCtx;
        this.ctx.save();
        this.ctx.setTransform(1, 0, 0, 1, 0, 0); 
        this.ctx.drawImage(this.transparentCanvas, 0, 0);
        this.ctx.restore();
        this.transparentCanvas = null;
      }
      this.cachedCanvases.clear();
      if (this.imageLayer) {
        this.imageLayer.endLayout();
      }
    }
    _scaleImage(img, inverseTransform) {