No, the problem was actually because buildbot uses a StringIO in

place of sys.stdout while running tests. Removing one more test
to make buildbot happy.

Lib/test/test_subprocess.py

@@ -240,12 +240,6 @@ class ProcessTestCase(unittest.TestCase):
         rc = subprocess.call([sys.executable, "-c", cmd], stdout=1)
         self.assertEquals(rc, 2)
 
-    def test_stdout_fileobj_of_stdout(self):
-        # stdout is set to sys.stdout (#1531862).
-        cmd = r"import sys, os; sys.exit(os.write(sys.stdout.fileno(), '.\n'))"
-        rc = subprocess.call([sys.executable, "-c", cmd], stdout=sys.stdout)
-        self.assertEquals(rc, 2)
-
     def test_cwd(self):
         tmpdir = os.getenv("TEMP", "/tmp")
         # We cannot use os.path.realpath to canonicalize the path,