fixes#24054
`readData` is not implemented for the VM as mentioned in the issue, but
`readDataStr` is, so that is used for `readStr` instead on the VM. We
could also just use it in general since it falls back to `readData`
anyway but it's kept the same otherwise for now.
Also where and why streams in general don't work in VM is now documented
on the top level `streams` module documentation.
080b0a03bd