Revert 47014 until it is more robust

Lib/test/test_wait4.py

@@ -2,7 +2,6 @@
 """
 
 import os
-import time
 from test.fork_wait import ForkWait
 from test.test_support import TestSkipped, run_unittest
 
@@ -18,13 +17,7 @@ except AttributeError:
 
 class Wait4Test(ForkWait):
     def wait_impl(self, cpid):
-        for i in range(10):
-            # wait4() shouldn't hang, but some of the buildbots seem to hang
-            # in the forking tests.  This is an attempt to fix the problem.
-            spid, status, rusage = os.wait4(cpid, os.WNOHANG)
-            if spid == cpid:
-                break
-            time.sleep(1.0)
+        spid, status, rusage = os.wait4(cpid, 0)
         self.assertEqual(spid, cpid)
         self.assertEqual(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8))
         self.assertTrue(rusage)