Make readdir() async, fix crash in large directory trees

[Jarred-Sumner]

No description provided.

[github-actions]

✅ test failures on linux-x64-baseline have been resolved.

^{#c4538823d85b4395ae2279395ab348ae9e8c4bfd}

[github-actions]

❌ @Jarred-Sumner 2 files with test failures on linux-x64:

• test/bundler/esbuild/splitting.test.ts
• test/js/bun/http/serve.test.ts

View test output

^{#c4538823d85b4395ae2279395ab348ae9e8c4bfd}

[github-actions]

❌ @Jarred-Sumner 3 files with test failures on bun-darwin-aarch64:

• test/bundler/esbuild/splitting.test.ts
• test/js/bun/spawn/spawn.test.ts
• test/js/bun/test/test-test.test.ts

View test output

^{#c4538823d85b4395ae2279395ab348ae9e8c4bfd}

[github-actions]

❌ @Jarred-Sumner 4 files with test failures on bun-darwin-x64-baseline:

• test/js/bun/spawn/spawn-streaming-stdin.test.ts
• test/js/bun/sqlite/sqlite.test.js
• test/js/third_party/webpack/webpack.test.ts
• test/js/web/timers/setTimeout.test.js

View test output

^{#c4538823d85b4395ae2279395ab348ae9e8c4bfd}