Change pattern triggering next step. (#12543)

Previously chosen pattern was generated in the output not quite at the end of the hot reload process.

dev/devicelab/lib/tasks/hot_mode_tests.dart

diff --git a/dev/devicelab/lib/tasks/hot_mode_tests.dart b/dev/devicelab/lib/tasks/hot_mode_tests.dart
index df339d7..583dbd9 100644
--- a/dev/devicelab/lib/tasks/hot_mode_tests.dart
+++ b/dev/devicelab/lib/tasks/hot_mode_tests.dart
@@ -44,7 +44,7 @@
           .transform(UTF8.decoder)
           .transform(const LineSplitter())
           .listen((String line) {
-          if (line.contains('\] Hot reload performed in')) {
+          if (line.contains('\] Reloaded ')) {
             if (hotReloadCount == 0) {
               // Update the file and reload again.
               final File appDartSource = file(path.join(