Because the part that is shared by `process.reallyExit` and the
Node.js teardown is `WaitForInspectorDisconnect()`, move that
into node_internals.h instead, and move the C++ binding code
into `node_process_methods.cc` since that's the only place
it's needed.

PR-URL: https://github.com/nodejs/node/pull/25860
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Minwoo Jung <minwoo@nodesource.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

Embedders may want to control whether a Node.js instance
controls the current process, similar to what we currently
have with `Worker`s.

Previously, the `isMainThread` flag had a bit of a double usage,
both for indicating whether we are (not) running a Worker and
whether we can modify per-process state.

PR-URL: https://github.com/nodejs/node/pull/25881
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Refs: https://github.com/nodejs/node/issues/25448
PR-URL: https://github.com/nodejs/node/pull/25526
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

Instead of in node_internals.h. Also move process property
accessors that are not reused into node_process_object.cc
and make them static.

PR-URL: https://github.com/nodejs/node/pull/25397
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

Changes `SetupProcessObject` to `CreateProessObject` which creates
the process object from scratch and return it to `Environment::Start`
to be stored in the Environment object.

PR-URL: https://github.com/nodejs/node/pull/25397
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>