filter some noisy messages from adb logcat

packages/flutter_tools/lib/src/android/android_device.dart

@@ -566,6 +566,10 @@ class _AdbLogReader extends DeviceLogReader {
   }
 
   void _onLine(String line) {
+    // Filter out some noisy ActivityManager notifications.
+    if (line.startsWith('W/ActivityManager: getRunningAppProcesses'))
+      return;
+
     _linesStreamController.add(line);
   }