Fix bug with readable streams that have been detached

[Jarred-Sumner]

What does this PR do?

Fixes #6200 (comment)
Fixes #6821

How did you verify your code works?

This needs a test. I haven't even manually tested this works.

[github-actions]

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

• test/cli/install/bunx.test.ts
• test/js/bun/test/test-test.test.ts
• test/js/web/fetch/body-stream.test.ts

View test output

^{#ea7a1c2687f693500070272a75b5bb5f19bc45c6}

[github-actions]

❌ @Jarred-Sumner 1 files with test failures on linux-x64:

• test/cli/install/bun-install.test.ts

View test output

^{#ea7a1c2687f693500070272a75b5bb5f19bc45c6}

[github-actions]

❌ @Jarred-Sumner 7 files with test failures on bun-darwin-x64-baseline:

• test/js/bun/spawn/spawn-streaming-stdout.test.ts
• test/js/bun/util/which.test.ts
• test/js/node/fs/fs.test.ts
• test/js/node/watch/fs.watchFile.test.ts
• test/js/third_party/postgres/postgres.test.ts
• test/js/third_party/webpack/webpack.test.ts
• test/js/web/timers/setTimeout.test.js

View test output

^{#ea7a1c2687f693500070272a75b5bb5f19bc45c6}