patch 7.4.1111
Problem:    test_expand fails on MS-Windows.
Solution:   Always use forward slashes.  Remove references to test27.
diff --git a/src/testdir/runtest.vim b/src/testdir/runtest.vim
index fd64c98..2a9231a 100644
--- a/src/testdir/runtest.vim
+++ b/src/testdir/runtest.vim
@@ -43,6 +43,9 @@
 " Output all messages in English.
 lang mess C
 
+" Always use forward slashes.
+set shellslash
+
 let s:srcdir = expand('%:p:h:h')
 
 " Support function: get the alloc ID by name.