src: use kInternalized instead of kNormal

Use v8::NewStringType::kInternalized instead of
v8::NewStringType::kNormal in different calls to v8::String::NewFromUtf8
in node.h and node.cc wherever it makes sense, to save the GC some work
which would largely be redundant.

PR-URL: https://github.com/nodejs/node/pull/21926


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: James M Snell <jasnell@gmail.com>