Fix ProgramPriorityTests on FreeBSD with high nice value (pythonGH-10…

…0145)

It expects priority to be capped with 19, which is the cap for Linux,
but for FreeBSD the cap is 20 and the test fails under the similar
conditions. Tweak the condition to cover FreeBSD as well.

Lib/test/test_os.py

@@ -3511,7 +3511,8 @@ def test_set_get_priority(self):
         os.setpriority(os.PRIO_PROCESS, os.getpid(), base + 1)
         try:
             new_prio = os.getpriority(os.PRIO_PROCESS, os.getpid())
-            if base >= 19 and new_prio <= 19:
+            # nice value cap is 19 for linux and 20 for FreeBSD
+            if base >= 19 and new_prio <= base:
                 raise unittest.SkipTest("unable to reliably test setpriority "
                                         "at current nice level of %s" % base)
             else: