src,doc,test: remove String::New default parameter

`kNormal` has been the implicit default for a while now (since V8 7.6).

Refs: https://github.com/v8/v8/commit/e0d7f816990ada28ebe1281ca9431236ef8c6e4f

Backport-PR-URL: https://github.com/nodejs/node/pull/34358
PR-URL: https://github.com/nodejs/node/pull/34248


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: James M Snell <jasnell@gmail.com>