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
```
currentX += img.width + 2 * IMAGE_PADDING;
      maxLineHeight = Math.max(maxLineHeight, img.height);
    }
    const imgWidth = Math.max(maxX, currentX) + IMAGE_PADDING;
    const imgHeight = currentY + maxLineHeight + IMAGE_PADDING;
    const imgData = new Uint8ClampedArray(imgWidth * imgHeight * 4);
    const imgRowSize = imgWidth << 2;
    for (let q = 0; q < count; q++) {
      const data = argsArray[iFirstPIIXO + (q << 2)][0].data;
      
      const rowSize = map[q].w << 2;
      let dataOffset = 0;
      let offset = (map[q].x + map[q].y * imgWidth) << 2;
      imgData.set(data.subarray(0, rowSize), offset - imgRowSize);
      for (let k = 0, kk = map[q].h; k < kk; k++) {
        imgData.set(data.subarray(dataOffset, dataOffset + rowSize), offset);
        dataOffset += rowSize;
        offset += imgRowSize;
      }
      imgData.set(data.subarray(dataOffset - rowSize, dataOffset), offset);
      while (offset >= 0) {
        data[offset - 4] = data[offset];
        data[offset - 3] = data[offset + 1];
        data[offset - 2] = data[offset + 2];
        data[offset - 1] = data[offset + 3];
        data[offset + rowSize] = data[offset + rowSize - 4];
        data[offset + rowSize + 1] = data[offset + rowSize - 3];
        data[offset + rowSize + 2] = data[offset + rowSize - 2];
        data[offset + rowSize + 3] = data[offset + rowSize - 1];
        offset -= imgRowSize;