chore(profiling): add non-running tests for stack v2

[sanchda]

This PR creates a harness for independently building and running the stack v2 code. I did it this way for a few reasons

• Don't want to add unnecessary overhead to our normal test process
• Want to run the build for these native components under multiple static analysis tools
• Want to run some of the tests for these components under sanitizers?
• But also want to do exhaustive testing of the interfaces, since we've had a few regressions here

This PR includes both the tests and the fixups they demand. A separate PR will add a CI job to execute these (or will add it to a pre-existing job, TBD).

There IS some dead code in here, since we do provide the recipe for getting and running Infer. During testing, I found that I couldn't reliably get infer to find stdlib headers, which completely broke the quality of its output, so it won't actually be used. At the same time, I think we might want to use it someday, and the setup is a little fiddly, so I'm including it here.

I'm recommending a backport to 2.7 for this because the latest 2.7 releases make this feature available, but the implementation is subtly (and sometimes not-so-subtly) broken without the fixups here. Since this feature is so isolated (I'm the only one backporting anything related!), this feels safe...ish.

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

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: sanchda/stackv2_initial_tests
Commit report: 13743c9
Test service: dd-trace-py

✅ 0 Failed, 171726 Passed, 1057 Skipped, 11h 28m 21.22s Total duration (39m 21.21s time saved)