Fix tests (#8736)

* do not forward status if stream is closed
* remove devfs test timeout

packages/flutter_tools/lib/src/commands/analyze_continuously.dart

@@ -238,7 +238,7 @@ class AnalysisServer {
 
   void _handleStatus(Map<String, dynamic> statusInfo) {
     // {"event":"server.status","params":{"analysis":{"isAnalyzing":true}}}
-    if (statusInfo['analysis'] != null) {
+    if (statusInfo['analysis'] != null && !_analyzingController.isClosed) {
       final bool isAnalyzing = statusInfo['analysis']['isAnalyzing'];
       _analyzingController.add(isAnalyzing);
     }

packages/flutter_tools/test/devfs_test.dart

@@ -269,9 +269,10 @@ void main() {
       ]);
       expect(devFS.assetPathsToEvict, isEmpty);
       expect(bytes, 48);
-    }, timeout: const Timeout(const Duration(seconds: 5)));
+    });
 
     testUsingContext('delete dev file system', () async {
+      expect(vmService.messages, isEmpty, reason: 'prior test timeout');
       await devFS.destroy();
       vmService.expectMessages(<String>['_deleteDevFS {fsName: test}']);
       expect(devFS.assetPathsToEvict, isEmpty);