[v2] fix: improved performance on multiple benchmarks

[darccio]

What does this PR do?

Fixes multiple regressions on v2-dev, resulting on appropriate performance - at par with main - in multiple areas.

Reviewer's Checklist

• Changed code has unit tests for its functionality at or near 100% coverage.
• System-Tests covering this feature have been added and enabled with the va.b.c-dev version tag.
• There is a benchmark for any new code, or changes to existing code.
• If this interacts with the agent in a new way, a system test has been added.
• Add an appropriate team label so this PR gets put in the right place for the release notes.
• Non-trivial go.mod changes, e.g. adding new modules, are reviewed by @DataDog/dd-trace-go-guild.
• For internal contributors, a matching PR should be created to the v2-dev branch and reviewed by @DataDog/apm-go.

Unsure? Have a question? Request a review!

[datadog-datadog-prod-us1]

Datadog Report

Branch report: dario.castane/langplat-168/bench-investigation
Commit report: fa0b980
Test service: dd-trace-go

✅ 0 Failed, 4095 Passed, 64 Skipped, 2m 51.15s Total Time