`info proc` doesn't work on replays

[GitMensch]

info proc mappings works fine, but the other parts of info proc, also requested in #1834, does not.

I've just rechecked: using "plain gdbserver + gdb" this works fine, a way to have this working in rr would be:

• include in trace and symlink similar to the proc mappings
  • /proc/$pid/cmdline
  • /proc/$pid/cwd
  • /proc/$pid/exe
• otherwise interrupt the calls from GDB requesting those (the remote GDB shows those from the inferior, so has to ask gdbserver for that)

If for some reason those cannot be intercepted, then a new command rr-info proc could show them.

Originally posted by @GitMensch in https://github.com/rr-debugger/rr/issues/2032#issuecomment-879091625

[vchuravy]

In particular I wanted infor proc stat today.

[GitMensch]

@vchuravy So possible "thumbs up" for the issue?