Prepare asgi tests to support newer asgiref version

[xrmx]

Description

This is trying to update the asgi tests, but this is draft because I'm not able to understand what's missing for middleware tests. It should be something trivial when interacting with the middleware because even basic tests are failing :)
Requires open-telemetry/opentelemetry-python#4106

Fixes #2776

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

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

• Test A

Does This PR Require a Core Repo Change?

• Yes. - Link to PR: opentelemetry-test-utils: add async base test class for asgi opentelemetry-python#4106
• 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

[drupol]

With the patches you made, we are now at:

 ================== 28 failed, 52 passed, 3 warnings in 2.26s ===================

Things are progressing in the right direction :)

[xrmx]

I won't be able to work on this for the next couple of weeks so please feel free to take over.

[drupol]

It's totally fine. I have no knowledge in this project and these technologies yet. In the meantime, we've disabled the tests in Nix (NixOS/nixpkgs@b7ac9d1), so this thing can wait, no worries.

[emdneto]

In the meantime, I'm making some progress in #2818. But a test is failing for Pypy, and I am still trying to figure out why. @drupol could you please test against #2818 while we fix the pypy failing test?