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
```
fnArray.splice(iFirstSave, count * 4, OPS.paintImageMaskXObjectGroup);
      argsArray.splice(iFirstSave, count * 4, [images]);
    }
    return iFirstSave + 1;
  }
);
addState(
  InitialState,
  [OPS.save, OPS.transform, OPS.paintImageXObject, OPS.restore],
  function (context) {
    const argsArray = context.argsArray;
    const iFirstTransform = context.iCurr - 2;
    return (
      argsArray[iFirstTransform][1] === 0 && argsArray[iFirstTransform][2] === 0
    );
  },
  function iterateImageGroup(context, i) {
    const fnArray = context.fnArray,
      argsArray = context.argsArray;
    const iFirstSave = context.iCurr - 3;
    const pos = (i - iFirstSave) % 4;
    switch (pos) {
      case 0:
        return fnArray[i] === OPS.save;
      case 1:
        if (fnArray[i] !== OPS.transform) {
          return false;
        }
        const iFirstTransform = context.iCurr - 2;
        const firstTransformArg0 = argsArray[iFirstTransform][0];