fix: revert #9113, #9114, #9085

[erikayasuda]

Reverting the following IAST PRs: #9113, #9114, #9085

They will be re-introduced in 2.10 after some investigation, but reverting for now to un-block the 2.9.0 release pipeline.

Checklist

• Change(s) are motivated and described in the PR description
• Testing strategy is described if automated tests are not included in the PR
• Risks are described (performance impact, potential for breakage, maintainability)
• Change is maintainable (easy to change, telemetry, documentation)
• Library release note guidelines are followed or label changelog/no-changelog is set
• Documentation is included (in-code, generated user docs, public corp docs)
• Backport labels are set (if applicable)
• If this PR changes the public interface, I've notified @DataDog/apm-tees.

Reviewer Checklist

• Title is accurate
• All changes are related to the pull request's stated goal
• Description motivates each change
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Change is maintainable (easy to change, telemetry, documentation)
• Release note makes sense to a user of the library
• Author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: erikayasuda/2.9revert
Commit report: dcff08c
Test service: dd-trace-py

✅ 0 Failed, 118066 Passed, 56097 Skipped, 2h 56m 54.7s Total duration (7h 33m 16.06s time saved)