Update test_eintr.py from Cpython v3.11.2

Lib/test/test_eintr.py

@@ -0,0 +1,20 @@
+import os
+import signal
+import unittest
+from test import support
+from test.support import script_helper
+
+
+@unittest.skipUnless(os.name == "posix", "only supported on Unix")
+class EINTRTests(unittest.TestCase):
+
+    @unittest.skipUnless(hasattr(signal, "setitimer"), "requires setitimer()")
+    def test_all(self):
+        # Run the tester in a sub-process, to make sure there is only one
+        # thread (for reliable signal delivery).
+        script = support.findfile("_test_eintr.py")
+        script_helper.run_test_script(script)
+
+
+if __name__ == "__main__":
+    unittest.main()