[infra] Make CI script GitHub aware

[dcharkes]

Recognize the script is running on GitHub and act accordingly:

• Test runner can report in a GitHub way.
• Don't skip the test locally that only fails on GitHub.
• Skip a second instance of the same test. ([native_toolchain_c] native_dynamic_linking_test access violation #2501)

[github-actions]

PR Health

Breaking changes ⚠️

Package	Change	Current Version	New Version	Needed Version	Looking good?
hooks	Breaking	0.20.0	0.20.1-wip	0.21.0 Got "0.20.1-wip" expected >= "0.21.0" (breaking changes)	⚠️
hooks_runner	Breaking	0.22.0	0.22.1-wip	0.23.0 Got "0.22.1-wip" expected >= "0.23.0" (breaking changes)	⚠️

This check can be disabled by tagging the PR with skip-breaking-check.

Changelog Entry ✔️

Package	Changed Files

Changes to files need to be accounted for in their respective changelogs.

API leaks ✔️

The following packages contain symbols visible in the public API, but not exported by the library. Export these symbols or remove them from your publicly visible API.

Package	Leaked API symbol	Leaking sources

License Headers ✔️

// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

Files
no missing headers

All source files should start with a license header.

Unrelated files missing license headers

Files
pkgs/jni/lib/src/third_party/generated_bindings.dart
pkgs/objective_c/lib/src/ns_input_stream.dart

[coveralls]

coverage: 71.971%. remained the same
when pulling ef2f043 on ci-tweaks
into 38b3789 on main.

[HosseinYousefi]

TIL about this flag!

[dcharkes]

I'm not sure it's working though. I see no difference in the CI...

[HosseinYousefi]

dart test --help says that it's the default on github CI so maybe it already picks up the env variable.

[github]                    A custom reporter for GitHub Actions (the default reporter when running on GitHub Actions).

[dcharkes]

I don't see any difference with a local run though? Or is it different in the fact that the local run does this replace-the-last-line?