dup and close file descriptors

[dylan-conway]

What does this PR do?

fixes #5435

• Documentation or TypeScript types (it's okay to leave the rest blank in this case)
• Code changes

How did you verify your code works?

[Jarred-Sumner]

are you sure we always call the unregister function before close?

[github-actions]

❌ @dylan-conway 1 files with test failures on linux-x64:

• test/bundler/esbuild/splitting.test.ts

View test output

^{#600685b587320534f9254e8179f1c2512041fcdf}

[github-actions]

❌ @dylan-conway 1 files with test failures on linux-x64-baseline:

• test/js/web/fetch/fetch-gzip.test.ts

View test output

^{#600685b587320534f9254e8179f1c2512041fcdf}

[github-actions]

❌ @dylan-conway 5 files with test failures on bun-darwin-aarch64:

• test/js/bun/spawn/spawn.test.ts
• test/js/bun/stream/direct-readable-stream.test.tsx
• test/js/bun/test/test-test.test.ts
• test/js/node/watch/fs.watch.test.ts
• test/js/web/worker.test.ts

View test output

^{#600685b587320534f9254e8179f1c2512041fcdf}

[github-actions]

❌ @dylan-conway 8 files with test failures on bun-darwin-x64-baseline:

• test/cli/install/bun-install.test.ts
• test/js/bun/spawn/spawn.test.ts
• test/js/bun/sqlite/sqlite.test.js
• test/js/node/fs/fs.test.ts
• test/js/node/watch/fs.watchFile.test.ts
• test/js/third_party/webpack/webpack.test.ts
• test/js/web/timers/setInterval.test.js
• test/js/web/timers/setTimeout.test.js

View test output

^{#600685b587320534f9254e8179f1c2512041fcdf}