[VM] Intermittent failure to bind to an ephemeral port

[annagrin]

We have seen flakes in flutter web tests recently due to failure to bind to an ephemeral port that is supposed to be free as chosen by the VM/OS.

See discussion in dart-lang/webdev#1451
See the parent flutter issue for details (flutter/flutter#93256). The stack trace:

[  +92 ms] SocketException: Failed to create server socket (OS Error: The shared flag to bind() needs to be `true` if binding multiple times on the same (address, port) combination.), address = ::1, port = 42919
     #0      _NativeSocket.bind (dart:io-patch/socket_patch.dart:988:7)
     <asynchronous suspension>
     #1      HttpMultiServer._loopback (package:http_multi_server/http_multi_server.dart:183:22)
     <asynchronous suspension>
     #2      ExtensionBackend.start (package:dwds/src/servers/extension_backend.dart:57:18)
     <asynchronous suspension>
     #3      Dwds.start (package:dwds/dwds.dart:138:26)
     <asynchronous suspension>
     #4      WebAssetServer.start (package:flutter_tools/src/isolated/devfs_web.dart:274:23)
     <asynchronous suspension>
     #5      WebDevFS.create (package:flutter_tools/src/isolated/devfs_web.dart:727:22)
     <asynchronous suspension>
     #6      ResidentWebRunner.run.<anonymous closure> (package:flutter_tools/src/isolated/resident_web_runner.dart:285:25)
     <asynchronous suspension>
     #7      asyncGuard.<anonymous closure> (package:flutter_tools/src/base/async_guard.dart:111:24)
     <asynchronous suspension>