This test is excluded on macOS due to platform-specific limitations:

REASON: system() and popen() with shell commands hang on macOS when the parent
process has active child processes. This test requires:
1. fork() and exec() to launch separate node processes
2. system() calls to verify process states
3. Inter-process communication with active ION daemons

The test launches multiple ION nodes as child processes and uses system() calls
to monitor and control them. These operations hang on macOS when child processes
are running ION daemons.

The core functionality tested (TCP convergence layer and multi-node communication)
is sufficiently covered by tests on Linux/Solaris where these system calls work
reliably.
