patch 9.0.0613: running source tests leaves file behind

Problem:    Running source tests leaves file behind.
Solution:   Add the "D" flag to writefile(). (Dominique Pellé, closes #11243)
            Also do this for other writefile() calls and drop delete().

src/version.c

@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    613,
 /**/
     612,
 /**/