build: make tools/doc/node_modules non-phony

This commit makes the target tools/doc/node_modules a non-phony target
and also adds tools/doc/package.json as a prerequisite to it to avoid
running it unnecessary. This is currently causing the target
test/addons/.docbuildstamp to be always be executed as it has
tools/doc/node_modules as a prerequisite.

PR-URL: https://github.com/nodejs/node/pull/22189


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Sam Ruby <rubys@intertwingly.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>