bpo-38203: faulthandler.dump_traceback_later() is always available (GH-16249)

dump_traceback_later() and cancel_dump_traceback_later() functions of
the faulthandler module are always available since Python 3.7.
diff --git a/Lib/test/test_faulthandler.py b/Lib/test/test_faulthandler.py
index 2448744..a4427a5 100644
--- a/Lib/test/test_faulthandler.py
+++ b/Lib/test/test_faulthandler.py
@@ -535,8 +535,6 @@
         with temporary_filename() as filename:
             self.check_dump_traceback_threads(filename)
 
-    @unittest.skipIf(not hasattr(faulthandler, 'dump_traceback_later'),
-                     'need faulthandler.dump_traceback_later()')
     def check_dump_traceback_later(self, repeat=False, cancel=False, loops=1,
                                    *, filename=None, fd=None):
         """
@@ -744,9 +742,8 @@
             faulthandler.enable()
         with self.check_stderr_none():
             faulthandler.dump_traceback()
-        if hasattr(faulthandler, 'dump_traceback_later'):
-            with self.check_stderr_none():
-                faulthandler.dump_traceback_later(1e-3)
+        with self.check_stderr_none():
+            faulthandler.dump_traceback_later(1e-3)
         if hasattr(faulthandler, "register"):
             with self.check_stderr_none():
                 faulthandler.register(signal.SIGUSR1)