Issue #19776: Fix test_pathlib.test_expanduser()

Skip users with an empty home directory.

Lib/test/test_pathlib.py

@@ -1983,7 +1983,7 @@ class PosixPathTest(_BasePathTest, unittest.TestCase):
         for pwdent in pwd.getpwall():
             othername = pwdent.pw_name
             otherhome = pwdent.pw_dir.rstrip('/')
-            if othername != username:
+            if othername != username and otherhome:
                 break
 
         p1 = P('~/Documents')