Change support for VM service message from "Dart VM Service listening" to "The Dart VM Service is listening" (flutter#31310)

See dart-lang/sdk#46756

Author: bkonyi

shell/testing/observatory/launcher.dart

@@ -35,7 +35,7 @@ class ShellProcess {
 
   Uri? _extractVMServiceUri(String str) {
     final listeningMessageRegExp = RegExp(
-      r'(?:Observatory|Dart VM Service) listening on ((http|//)[a-zA-Z0-9:/=_\-\.\[\]]+)',
+      r'(?:Observatory|The Dart VM Service is) listening on ((http|//)[a-zA-Z0-9:/=_\-\.\[\]]+)',
     );
     final match = listeningMessageRegExp.firstMatch(str);
     if (match != null) {

testing/android_systrace_test.py

@@ -61,7 +61,7 @@ def LaunchPackage(package_name, activity_name, adb_path='adb'):
           '%s/%s' % (package_name, activity_name)], stderr=subprocess.STDOUT)
   for line in logcat.stdout:
     print('>>>>>>>> ' + line.strip())
-    if ('Observatory listening' in line) or ('Dart VM Service listening' in line):
+    if ('Observatory listening' in line) or ('Dart VM Service is listening' in line):
       logcat.kill()
       break