Run daemon communication tests only on Linux

For some reason, the CI runs on Github Actions block the macOS runners,
and they take forever to run the tests. The tests are really needed only
on Linux, and the errno values that it uses are only verified to work on
Linux.

daemon/test_daemon_comm.py

@@ -4,6 +4,7 @@
 import glob
 import os
 import os.path
+import platform
 import shlex
 import signal
 import socket
@@ -173,6 +174,11 @@ class Test:
 
 def main():
     """Main routine adds test cases to the Test class and runs them"""
+    # Only run the tests on Linux platform
+    if platform.system() != 'Linux':
+        print('1..0 # Skipping tests on', platform.system())
+        return
+
     with Test() as test:
         test.find_and_parse_testcase_files()
         test.run_tests()