standalone/io/socket_udp_readwrite_test timing out on Windows configurations

[sstrickl]

There are new test failures on [io/socket/win] Ensure udp sockets survive sending data to unreachable destination..

The tests

standalone/io/socket_udp_readwrite_test Timeout (expected Pass)

are failing on configurations

vm-aot-win-product-x64

Looking at the current results, it looks like the other Windows configurations are also flakily timing out.

/cc @aam

[aam]

thank you @sstrickl .
https://dart-review.googlesource.com/c/sdk/+/391305 with the fix.