patch 9.0.0381: writefile test leaves files behind

Problem:    Writefile test leaves files behind.
Solution:   Fix the file names of files to be deleted. (Dominique Pellé,
            closes #11056)

src/testdir/test_writefile.vim

@@ -75,8 +75,8 @@ func Test_writefile_fails_conversion()
   call assert_match('CONVERSION ERROR', output)
   let output = execute('write! ++enc=ucs-2 Xwfcfile')
   call assert_match('CONVERSION ERROR', output)
-  call delete('Xfilz~')
-  call delete('Xfily~')
+  call delete('Xwfcfilz~')
+  call delete('Xwfcfily~')
   %bw!
 
   call delete('Xwfcfile')

src/version.c

@@ -703,6 +703,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    381,
 /**/
     380,
 /**/