library: std: motor: use OS' process::exit in abort_internal
abort_internal() is used in panics; if it calls core::intrinsics::abort(), the process triggers an invalid op code (on x86_64), which is a much harder "abort" than a user-controlled exit via a panic.
Most other OSes don't use core::intrinsics::abort() here, but either libc::abort(), or a native OS abort/exit API.
Jonathan Brouwer
87b48159c3