Ensure async generators are awaited

[rrjjvv]

Description

This change simply awaits coroutines that are not being processed; it basically corrects #2541. There is no new functionality and no new dependencies.

Fixes #2791

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• The reproduction in asyncio instrumentation does not await generator coroutines #2791 (self-explanatory) and my own (proprietary) application

Does This PR Require a Core Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

[linux-foundation-easycla]

• ✅login: rrjjvv / (b6811a8)
• ✅login: rrjjvv / (b6811a8, a323844)

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[rrjjvv]

Technically I didn't add tests; since the existing test was arguably incomplete, I thought it would be better and clearer to just fix the existing test. I'd be happy to revert it and create a dedicated test if that's preferred.