bpo-36236: Handle removed cwd at Python init (GH-12450)

At Python initialization, the current directory is no longer
prepended to sys.path if it has been removed.
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index cdc2edf..c01a04e 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -2615,7 +2615,10 @@
     if (updatepath) {
         /* If argv[0] is not '-c' nor '-m', prepend argv[0] to sys.path.
            If argv[0] is a symlink, use the real path. */
-        PyObject *argv0 = _PyPathConfig_ComputeArgv0(argc, argv);
+        PyObject *argv0 = NULL;
+        if (!_PyPathConfig_ComputeArgv0(argc, argv, &argv0)) {
+            return;
+        }
         if (argv0 == NULL) {
             Py_FatalError("can't compute path0 from argv");
         }