src: remove pushValueToArray and SetupProcessObject

The usage of NODE_PUSH_VAL_TO_ARRAY_MAX and
push_values_to_array_function has all been removed
in favor of the new Array::New API that takes a C++
array. Remove the unused code.

PR-URL: https://github.com/nodejs/node/pull/24264


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>