patch 8.0.0338: :recover test fails on MS-Windows

Problem:    :recover test fails on MS-Windows.
Solution:   Use non-existing directory on MS-Windows.

src/testdir/test_recover.vim

@@ -7,6 +7,10 @@ func Test_recover_root_dir()
   call assert_fails('recover', 'E305:')
   close!
 
+  if has('win32')
+    " can write in / directory on MS-Windows
+    set dir=/notexist/
+  endif
   call assert_fails('split Xtest', 'E303:')
   set dir&
 endfunc

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    338,
 /**/
     337,
 /**/