Patch test_posixpath for huge pwd.getpwall() output

Summary: In certain environments, `pwd.getpwall()` can return very long lists. Having the test iterate on the full list isn't very useful for the purpose of the test (it's just testing the same thing over and over), but can dramatically increase the runtime of the test (as long as ~10m).

Reviewed By: parulgupta1004

Differential Revision: D69377194

fbshipit-source-id: 36dbd37eb31f228f514cf6e46ee91b8efe4a1519

Lib/test/test_posixpath.py

@@ -347,7 +347,7 @@ def test_expanduser_pwd(self):
                      "no home directory on VxWorks")
     def test_expanduser_pwd2(self):
         pwd = import_helper.import_module('pwd')
-        for e in pwd.getpwall():
+        for e in pwd.getpwall()[:10]:
             name = e.pw_name
             home = e.pw_dir
             home = home.rstrip('/') or '/'