Automatically name forked processes based on callers

[vinistock]

From time to time, we have reports of extra child processes being created by the runtime server. It's hard to figure out where these are coming from because the user's application could be the one creating them. It could also be Tapioca or some other add-on.

This PR patches fork to always name the forked process using the file path of the caller, so that we know where fork was called. While caller_locations is a bit expensive, I think it's worth the extra help in debugging. Please let me know if you agree.

[vinistock]

• #633 👈 (View in Graphite)
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[vinistock]

For some reason, tests are hanging with this change. Not sure why.