Convert shell scripts to dart scripts

Look into converting the following over to dart scripts:

All the CI scripts under `tool/ci`:
- [ ] benchmark_performance.sh
- [ ] benchmark_size.sh
- [ ] bots.sh
- [ ] package_tests.sh
- [ ] setup.sh

All other scripts:
- [x] build_release.sh - replaced by `devtools_tool build-release`
- [x] fix_goldens.sh - replaced by `devtools_tool fix-goldens --run-id 12345`
- [x] ~flutter_tests.sh~ (no longer exists). We have remaining bash scripts under `flutter_customer_tests` but these do not need to be run on Windows right now.
- [x] generate_code.sh - https://github.com/flutter/devtools/pull/6579
- [ ] latest_flutter_candidate.sh
- [x] pub_upgrade.sh - replaced by `devtools_tool pub-get --upgrade`
- [x] pull_and_refresh.sh - replaced by `devtools_tool sync`
- [x] refresh.sh - replaced by `devtools_tool generate-code --upgrade`
- [x] release_helper.sh
- [x] tag_version.sh - replaced by `devtools_tool tag-version`
- [x] update_flutter_sdk.sh - replaced by `devtools_tool update-flutter-sdk [--local] [--no-use-cache]`
- [x] update_perfetto.sh - replaced by `devtools_tool update-perfetto`
- [x] upgrade.sh - replaced by the `pub-get` command: `devtools_tool pub-get --only-main --upgrade`
- [x] `build_e2e.dart` should also be moved into `devtools_tool` for consistency
- this has been replaced by `devtools_tool serve`