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
```
function (reason) {
          expect(reason instanceof Error).toEqual(true);
        }
      );
      arrayPromise = arrayPromise.then(
        function () {
          throw new Error("shall fail for non-string destination.");
        },
        function (reason) {
          expect(reason instanceof Error).toEqual(true);
        }
      );
      await Promise.all([numberPromise, booleanPromise, arrayPromise]);
    });
    it("gets non-existent page labels", async function () {
      const pageLabels = await pdfDocument.getPageLabels();
      expect(pageLabels).toEqual(null);
    });
    it("gets page labels", async function () {
      
      const loadingTask0 = getDocument(buildGetDocumentParams("bug793632.pdf"));
      const promise0 = loadingTask0.promise.then(function (pdfDoc) {
        return pdfDoc.getPageLabels();
      });
      
      const loadingTask1 = getDocument(buildGetDocumentParams("issue1453.pdf"));
      const promise1 = loadingTask1.promise.then(function (pdfDoc) {
        return pdfDoc.getPageLabels();
      });