patch 8.0.1634: the ex_vimgrep() function is too long

Problem:    The ex_vimgrep() function is too long.
Solution:   Split it in smaller functions. (Yegappan Lakshmanan)

src/version.c

@@ -766,6 +766,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1634,
 /**/
     1633,
 /**/