Disable some testing on Windows while examining the problem

tests/standalone/io/http_content_length_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "dart:isolate";
 import "dart:io";
 
 void testNoBody(int totalConnections, bool explicitContentLength) {
   HttpServer server = new HttpServer();
   server.onError = (e) => Expect.fail("Unexpected error $e");
@@ skipping 175 matching lines @@
       server.close();
     };
   };
 }
 
 void main() {
   testNoBody(5, false);
   testNoBody(5, true);
   testBody(5, false);
   testBody(5, true);
-  testBodyChunked(5, false);
-  testBodyChunked(5, true);
+  // These tests can fail or timeout on Windows, issue 7562.
+  if (Platform.operatingSystem != 'windows') {
+    testBodyChunked(5, false);
+    testBodyChunked(5, true);
+  }
   testHttp10();
 }