As discussed in https://github.com/nodejs/node/pull/45888, using a
global `BuiltinLoader` instance is probably undesirable in a world
in which embedders are able to create Node.js Environments with
different sources and therefore mutually incompatible code
caching properties.
This PR makes it so that `BuiltinLoader` is no longer a global
singleton and instead only shared between `Environment`s that
have a direct relation to each other, and addresses a few
thread safety issues along with that.
PR-URL: https://github.com/nodejs/node/pull/45942
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Anna Henningsen
d896f5befd