Fix UDPSocket not being closed when VM destructs

[190n]

What does this PR do?

Fixes lifetime bugs in the UDPSocket implementation. In particular, the socket would not be closed if the VM exited before it was garbage collected. This means file descriptors would leak if worker threads are rapidly created and open UDP sockets.

TODOs before merging:

• fix the objects not getting GC'd until VM exits
• rebase this on main once the branch ben/workers is merged

How did you verify your code works?

TODO (this probably deserves new tests)

[robobun]

^{Updated 4:31 PM PT - Mar 31st, 2025}

❌ @190n, your commit 2f2b530 has 2 failures in Build #14317:

• test/js/node/test/parallel/test-worker-process-exit-async-module.js - code 1 on 🐧 24.04 aarch64
• test/js/node/test/parallel/test-worker-process-exit-async-module.js - code 1 on 🐧 12 aarch64
• test/js/node/test/parallel/test-worker-process-exit-async-module.js - code 1 on 🐧 22.04 aarch64
• test/js/node/test/parallel/test-worker-process-exit-async-module.js - code 1 on 🐧 20.04 aarch64
• test/js/node/test/parallel/test-worker-terminate-unrefed.js - code 1 on 🍎 14 aarch64
• test/js/node/test/parallel/test-worker-terminate-unrefed.js - code 1 on 🪟 2019 x64-baseline
• test/js/node/test/parallel/test-worker-terminate-unrefed.js - code 1 on 🪟 2019 x64
• test/js/node/test/parallel/test-worker-terminate-unrefed.js - code 1 on 🐧 3.21 x64
• test/js/node/test/parallel/test-worker-terminate-unrefed.js - code 1 on 🐧 22.04 x64-baseline
• test/js/node/test/parallel/test-worker-terminate-unrefed.js - code 1 on 🐧 24.04 x64-baseline
• test/js/node/test/parallel/test-worker-terminate-unrefed.js - code 1 on 🐧 12 x64
• test/js/node/test/parallel/test-worker-terminate-unrefed.js - code 1 on 🐧 20.04 x64
• test/js/node/test/parallel/test-worker-terminate-unrefed.js - code 1 on 🐧 20.04 x64-baseline
• test/js/node/test/parallel/test-worker-terminate-unrefed.js - code 1 on 🐧 22.04 x64
• test/js/node/test/parallel/test-worker-terminate-unrefed.js - code 1 on 🐧 24.04 x64

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🧪   try this PR locally:

bunx bun-pr 18687