Fix kill signal on Windows

tests/test_concurrency.py

@@ -4,6 +4,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+import os
 
 import pytest
 
@@ -12,7 +13,8 @@ from ocrmypdf import ExitCode
 from .conftest import run_ocrmypdf_api
 
 
-def test_child_page4(resources, no_outpdf):
+@pytest.mark.skipif(os.name == 'nt', reason="Windows doesn't have SIGKILL")
+def test_simulate_oom_killer(resources, no_outpdf):
     exitcode = run_ocrmypdf_api(
         resources / 'multipage.pdf',
         no_outpdf,