fix(node:http) Export validateHeaderName and validateHeaderValue functions

[mash-graz]

Modify _http_outgoing.ts to support the extended signature of validateHeaderName() used since node v19.5.0/v18.14.0 by adding the label parameter. (see: https://nodejs.org/api/http.html#httpvalidateheadernamename-label)

Making both validation functions accessible as public exports of node:http

Fixes: #22614

[CLAassistant]

All committers have signed the CLA.

[aapoalas]

Formatting check fails.

Also, could you add "test-http-header-validators.js" string to tests/node_compat/config.jsonc line 369. I think that should enable the tests for these.

[aapoalas]

Here's a good example of what enabling a node test entails: https://github.com/denoland/deno/pull/22489/files#diff-66a13180ca921c746469f8f0bf6ec0cafab925839d65fdca6379866c4bb7be40

Note this part:

NOTE: This file should not be manually edited. Please edit tests/node_compat/config.json and run deno task setup in tools/node_compat dir instead.

[mash-graz]

The fmt issues should be now fixed and a relevant node_compat test is also activated.

Please review again.

[mash-graz]

Please take a look at this more or less trivial modifications and merge them!

The included changes are so simple, that I didn't open a new branch when I opened this PR, but in the meantime I prepared a lot of other more extensive patches for deno, which I can't simply transfer to github, because this PR and it's fixed source branch location are blocking all my further activities... :(

sorry!

[bartlomieju]

LGTM, thanks, good fix.

addressed