Fix ROCm test builds and enable activity profiler tests

[scotts]

We make three changes:

1. We were not properly turning on ROCm builds for CI tests. Fixes that.
2. Changes the tests to use nlohmann/json instead of folly's json. This makes it easier to test on GitHub CI as we don't have folly included as an external dependency yet. However, we're doing this through our third-party dependency on dynolog, which is perhaps not ideal. We can explore adding nlohmann/json as a direct third party dependency later.
3. Enables CUPTI activity profiler test and creates new test target for ROCm activity profiler test.

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[meta-codesync]

@scotts has imported this pull request. If you are a Meta employee, you can view this in D94228170.

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@scotts has updated the pull request. You must reimport the pull request before landing.

[meta-codesync]

@scotts merged this pull request in 7023dae.