bpo-42249: Fix writing binary Plist files larger than 4 GiB. (GH-23121)

(cherry picked from commit 212d32f45c91849c17a82750df1ac498d63976be)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
diff --git a/Lib/plistlib.py b/Lib/plistlib.py
index 83b214e..2eeebe4 100644
--- a/Lib/plistlib.py
+++ b/Lib/plistlib.py
@@ -611,7 +611,7 @@
     elif count < 1 << 16:
         return 2
 
-    elif count << 1 << 32:
+    elif count < 1 << 32:
         return 4
 
     else: