Fix #9600. Don't use relative imports for _multiprocessing on Windows.
Same fix as #9513 on 3.x.
diff --git a/Lib/multiprocessing/connection.py b/Lib/multiprocessing/connection.py
index b1f5acd..99b338e 100644
--- a/Lib/multiprocessing/connection.py
+++ b/Lib/multiprocessing/connection.py
@@ -173,7 +173,7 @@
 
 else:
 
-    from ._multiprocessing import win32
+    from _multiprocessing import win32
 
     def Pipe(duplex=True):
         '''