bpo-38075: Fix random_seed(): use PyObject_CallOneArg() (GH-18897)

Fix the random.Random.seed() method when a bool is passed as the
seed.

PyObject_Vectorcall() was misused: use PyObject_CallOneArg() instead.
diff --git a/Lib/test/test_random.py b/Lib/test/test_random.py
index 2c8c8e8..c147105 100644
--- a/Lib/test/test_random.py
+++ b/Lib/test/test_random.py
@@ -42,7 +42,7 @@
             def __hash__(self):
                 return -1729
         for arg in [None, 0, 1, -1, 10**20, -(10**20),
-                    3.14, 'a']:
+                    False, True, 3.14, 'a']:
             self.gen.seed(arg)
 
         for arg in [1+2j, tuple('abc'), MySeed()]: