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ARROW-6767: [JS] Lazily bind batches in scan/scanReverse

I noticed some `TODO` comments in the JS client library that expressed interest in calling `bind(batch)` lazily. This PR implements that optimization and updates related tests.

Happy to make updates per feedback!

Created a JIRA issue [here](https://issues.apache.org/jira/browse/ARROW-6767).

Closes #5565 from rolyatmax/tb/lazily-bind-batches and squashes the following commits:

8877a8f8f <Taylor Baldwin> ARROW-6767:  lazily bind batches in scan/scanReverse

Authored-by: Taylor Baldwin <tbaldwin@uber.com>
Signed-off-by: Krisztián Szűcs <szucs.krisztian@gmail.com>