v2: fix divergent changes

[hannahkm]

What does this PR do?

This PR addresses divergences that arose from creating v2 of dd-trace-go. It aims to maintain the behavior of v1 as closely as possible, address linting (such as clarifying comments, removing miscellaneous log statements, and removing unused code), and otherwise cleaning up the v2 code.

Motivation

Maintaining v2 while v1 is still active can introduce diverging changes, which we should address before release.

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.

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[pr-commenter]

Benchmarks

Benchmark execution time: 2024-09-19 20:32:41

Comparing candidate commit 485f5d8 in PR branch hannah/divergences with baseline commit 7d4b68c in branch v2-dev.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 53 metrics, 0 unstable metrics.