defaultOverridesFilePath function
Absolute path of the side-channel file under rootPath (defaults to cwd). The reporter calls this
to compute the value it exports as overridesEnvVar to the subprocess.
Implementation
String defaultOverridesFilePath([String? rootPath]) {
final segments = _overridesRelativePath.split('/');
return [rootPath ?? Directory.current.path, ...segments]
.join(Platform.pathSeparator);
}