`build_flags` are not picked up when running tests

I would have expected `build_flags` to follow the same behavior as a build flag in a `.bazelrc` and be included in test targets. This does not appear to be the case. Could this either be fixed or clarified somewhere?

No files or tests are named. Inspect the repository's Bazel CI configuration and compare how build_flags are handled with the equivalent .bazelrc behavior, then reproduce the behavior for test targets. Done means either the flags are applied consistently to tests or the differing behavior is clearly documented.

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