For htsget variants source and visibilityWindow = -1 IGV get data only for one chromosome

[RoadRoller]

igv.js version: 2.13.11

Steps to reproduce:

1. configure variants track with htsget source and visibilityWindow = -1

{
        name: 'My variants',
        url: <URL_TO_HTSGET_SERVER>,
        type: "variant",
        format: "vcf",
        sourceType: 'htsget',
        visibilityWindow: -1,
      }

2. Open IGV with track and select some chromosome - variants displayed as expected
3. Switch to another chromosome - results are empty, expected variants for selected chromosome

[jrobinso]

Unfortunately I do not have access to an htsget server anymore, the public endpoint from GA4GH has been broken for over a year. So I'm not able to support htsget at this time.

See ga4gh/htsget-refserver#33