bpo-31999: Fix test_venv in case the zlib module is not available. (GH-4359) (#4360)

(cherry picked from commit 5e0df74b)

Lib/test/test_venv.py

@@ -13,7 +13,7 @@ import struct
 import subprocess
 import sys
 import tempfile
-from test.support import (captured_stdout, captured_stderr,
+from test.support import (captured_stdout, captured_stderr, requires_zlib,
                           can_symlink, EnvironmentVarGuard, rmtree)
 import unittest
 import venv
@@ -424,6 +424,7 @@ class EnsurePipTest(BaseTest):
                                     ' module unconditionally')
     # Issue #26610: pip/pep425tags.py requires ctypes
     @unittest.skipUnless(ctypes, 'pip requires ctypes')
+    @requires_zlib
     def test_with_pip(self):
         self.do_test_with_pip(False)
         self.do_test_with_pip(True)