avoid creating Jackson parser explicitly

[pjfanning]

Pull Request Checklist

• Have you read through the contributor guidelines?
• Have you squashed your commits?
• Have you added copyright headers to new files?
• Have you updated the documentation?
• Have you added tests for any changed functionality?

Fixes

Not needed if #1280 is merged

Purpose

What does this PR do?

Let Jackson create the parser itself under the hood.

Background Context

Why did you take this approach?

References

Are there any relevant issues / PRs / mailing lists discussions?

[gaeljw]

Somehow I missed this PR. I think it still makes sense even with #1280, I haven't changed the read methods. But we could merge this PR into the #1280 maybe indeed as it's similar.

[pjfanning]

@mkurz would it be possible to consider merging this?

[mkurz]

• Document InputStream ownership #1361