"flutter daemon" leaves orphaned "xcdevice observe" processes around after being terminated #73859
Description
I can't repro this from the terminal (though that uses SIGINT on Ctrl+C and we generally), but from VS Code (which uses SIGTERM for all of its spawned processes) or the script below, the device daemon leaves behind some orphaned xcdevice proceses.
The script spawns the daemon, waits 10 seconds, then calls .kill(). After it completes, a /Applications/Xcode.app/Contents/Developer/usr/bin/xcdevice observe --both process remains. If I open/close lots of projects in VS Code, they will build up.
I'm testing with the latest master branch.
import 'dart:convert';
import 'dart:io';
Future<void> main(List<String> arguments) async {
print('Spawning...');
final proc = await Process.start('flutter', ['daemon']);
proc.stderr.transform(utf8.decoder).listen(print);
proc.stdout.transform(utf8.decoder).listen(print);
await Future.delayed(const Duration(seconds: 1));
print('Enabling devices...');
proc.stdin.writeln('[{"id":"2","method":"device.enable"}]');
await Future.delayed(const Duration(seconds: 10));
print('Terminating...');
proc.kill();
print('Done!');
}