tests: Fix compile errors after tools upgrade.

testsuite/arphole/test_main.c

@@ -49,6 +49,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 #include <rtems/bsd/util.h>
 

testsuite/loopback01/test_main.c

@@ -22,6 +22,7 @@
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <sysexits.h>
+#include <unistd.h>
 
 #include <machine/rtems-bsd-commands.h>