Make devicelab count as a bot so we can see crash logs (#7687)

dev/devicelab/lib/framework/utils.dart

@@ -165,6 +165,8 @@ Future<Process> startProcess(
 }) async {
   String command = '$executable ${arguments?.join(" ") ?? ""}';
   print('Executing: $command');
+  environment ??= <String, String>{};
+  environment['BOT'] = 'true';
   Process process = await Process.start(
     executable,
     arguments,

packages/flutter_tools/lib/src/base/utils.dart

@@ -17,6 +17,7 @@ bool get isRunningOnBot {
   // CHROME_HEADLESS is one property set on Flutter's Chrome Infra bots.
   return
     platform.environment['TRAVIS'] == 'true' ||
+    platform.environment['BOT'] == 'true' ||
     platform.environment['CONTINUOUS_INTEGRATION'] == 'true' ||
     platform.environment['CHROME_HEADLESS'] == '1';
 }