Disable CPU frequency test if no task affinity

testsuite/expect/test1.75

@@ -64,6 +64,10 @@ if {[slurmd_user_root] == 0} {
 	send_user "\nWARNING: This test is incompatible with SlurmdUser != root\n"
 	exit 0
 }
+if {[test_cpu_affinity_or_cgroup] == 0} {
+	send_user "\nWARNING: This test requires some form of task affinity\n"
+	exit 0
+}
 
 proc sub_job { freq } {