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
```
const groupCtx = this.ctx;
      this.groupLevel--;
      this.ctx = this.groupStack.pop();
      composeSMask(this.ctx, this.current.activeSMask, groupCtx);
      this.ctx.restore();
      this.ctx.save(); 
      copyCtxState(groupCtx, this.ctx);
      
      this.current.resumeSMaskCtx = groupCtx;
      
      
      const deltaTransform = Util.transform(
        this.current.activeSMask.startTransformInverse,
        groupCtx.mozCurrentTransform
      );
      this.ctx.transform.apply(this.ctx, deltaTransform);
      
      groupCtx.save();
      groupCtx.setTransform(1, 0, 0, 1, 0, 0);
      groupCtx.clearRect(0, 0, groupCtx.canvas.width, groupCtx.canvas.height);
      groupCtx.restore();
    }
    resumeSMaskGroup() {