fix(dev): wait until app server is killed before starting a new app server

[pcattori]

Fixes #6283

Testing: Added a setTimeout locally to artificially delay p.kill to simulate a slow-to-kill process for the app server. Confirmed that this code was resilient and waited for process to be killed before proceeding to spin up new app server instance and that EADDRINUSE was not encountered.

[changeset-bot]

🦋 Changeset detected

Latest commit: 0004c51

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 18 packages

Name	Type
@remix-run/dev	Patch
create-remix	Patch
@remix-run/css-bundle	Patch
remix	Patch
@remix-run/architect	Patch
@remix-run/cloudflare	Patch
@remix-run/cloudflare-pages	Patch
@remix-run/cloudflare-workers	Patch
@remix-run/deno	Patch
@remix-run/eslint-config	Patch
@remix-run/express	Patch
@remix-run/netlify	Patch
@remix-run/node	Patch
@remix-run/react	Patch
@remix-run/serve	Patch
@remix-run/server-runtime	Patch
@remix-run/testing	Patch
@remix-run/vercel	Patch

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[pcattori]

Need to see if we can do better than taskkill on Windows: nodejs/node#12378

[github-actions]

🤖 Hello there,

We just published version 1.16.1-pre.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!