Fix adapter request creation when double slashes exist

[brophdawg11]

The root cause of this came down to us passing the origin in the optional second base param for the new URL() constructor. When we did this, an incoming pathname of // got incorrectly identified as a protocol-less absolute URL. Since we know the origin, we can just pass an absolute URL directly into the first param to avoid this:

let origin = 'http://localhost';
let path = '//';

// ❌ Throws `Invalid URL` error
new URL(path, origin);

// ✅ All good in the hood
new URL(`${origin}${path}`);

Closes: #4422
Replace #4622

• Docs
• Tests

Testing Strategy:

• Unit tests for each of the adapters
• Manual testing for express

⚠️ Note this does not change anything about our route matching logic, it just lets the request make it through to matching. Current behavior is as follows:

• // will match a root/index route
• //todos will 404 if a /todos route exists

[changeset-bot]

🦋 Changeset detected

Latest commit: 7bb4fbe

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

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[github-actions]

🤖 Hello there,

We just published version v0.0.0-nightly-7f3c92b-20230202 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!