Issue #17928: Fix test_structmembers on 64-bit big-endian machines.

(_testcapi isn't Py_ssize_t-clean, the "s#" code should use an int for length)
diff --git a/Misc/NEWS b/Misc/NEWS
index 466781c..579e09c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -97,6 +97,8 @@
 Tests
 -----
 
+- Issue #17928: Fix test_structmembers on 64-bit big-endian machines.
+
 - Issue #17883: Fix buildbot testing of Tkinter on Windows.
   Patch by Zachary Ware.