fix(iast): remove unneeded atexit handler

[gnufede]

IAST: This fix addresses an issue where the atexit handler could lead to a segmentation fault.

Fixes #8504

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.
• If change touches code that signs or publishes builds or packages, or handles credentials of any kind, I've requested a review from @DataDog/security-design-and-guidance.

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

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-03-04 19:13:38

Comparing candidate commit 469665a in PR branch gnufede/test-no-initializer-reset with baseline commit 6592d5d in branch main.

Found 10 performance improvements and 7 performance regressions! Performance is the same for 186 metrics, 9 unstable metrics.

scenario:coreapiscenario-context_with_data_listeners_and_all_listeners

• 🟩 max_rss_usage [-809.286KB; -652.986KB] or [-2.699%; -2.178%]

scenario:coreapiscenario-context_with_data_only_all_listeners

• 🟩 max_rss_usage [-983.970KB; -824.004KB] or [-3.285%; -2.751%]

scenario:coreapiscenario-core_dispatch_listeners

• 🟥 max_rss_usage [+591.756KB; +773.032KB] or [+2.015%; +2.633%]

scenario:coreapiscenario-core_dispatch_with_results_listeners

• 🟩 max_rss_usage [-891.718KB; -733.574KB] or [-2.980%; -2.452%]

scenario:flasksimple-tracer

• 🟥 execution_time [+224.144µs; +275.732µs] or [+3.557%; +4.375%]

scenario:httppropagationextract-all_styles_all_headers

• 🟥 max_rss_usage [+0.961MB; +1.080MB] or [+3.305%; +3.718%]

scenario:httppropagationextract-b3_headers

• 🟩 max_rss_usage [-763.593KB; -658.539KB] or [-2.541%; -2.192%]

scenario:httppropagationextract-invalid_priority_header

• 🟥 max_rss_usage [+684.484KB; +800.316KB] or [+2.336%; +2.731%]

scenario:httppropagationextract-tracecontext_headers

• 🟩 max_rss_usage [-739.257KB; -635.770KB] or [-2.461%; -2.117%]

scenario:httppropagationextract-valid_headers_all

• 🟩 max_rss_usage [-773.392KB; -662.256KB] or [-2.577%; -2.207%]

scenario:httppropagationextract-wsgi_large_header_no_matches

• 🟩 max_rss_usage [-860.407KB; -720.649KB] or [-2.859%; -2.395%]

scenario:httppropagationextract-wsgi_large_valid_headers_all

• 🟩 max_rss_usage [-839.075KB; -726.007KB] or [-2.790%; -2.414%]

scenario:httppropagationextract-wsgi_medium_header_no_matches

• 🟩 max_rss_usage [-829.110KB; -719.178KB] or [-2.756%; -2.391%]

scenario:httppropagationextract-wsgi_medium_valid_headers_all

• 🟩 max_rss_usage [-727.552KB; -614.298KB] or [-2.423%; -2.046%]

scenario:otelspan-start-finish

• 🟥 max_rss_usage [+640.643KB; +805.654KB] or [+2.092%; +2.631%]

scenario:otelspan-start-finish-telemetry

• 🟥 max_rss_usage [+662.991KB; +760.369KB] or [+2.164%; +2.482%]

scenario:span-add-metrics

• 🟥 max_rss_usage [+25.758MB; +25.879MB] or [+65.907%; +66.218%]

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: gnufede/test-no-initializer-reset
Commit report: ecb98e4
Test service: dd-trace-py

✅ 0 Failed, 91564 Passed, 19739 Skipped, 46m 38.45s Total duration (1h 8m 56.35s time saved)