patch 8.1.0635: Coverity complains about null pointer use

Problem:    Coverity complains about null pointer use.
Solution:   Avoid using a null pointer.

Author: brammool

src/evalfunc.c

@@ -13586,7 +13586,7 @@ f_test_override(typval_T *argvars, typval_T *rettv UNUSED)
 	EMSG(_(e_invarg));
     else
     {
-	name = tv_get_string_chk(&argvars[0]);
+	name = tv_get_string(&argvars[0]);
 	val = (int)tv_get_number(&argvars[1]);
 
 	if (STRCMP(name, (char_u *)"redraw") == 0)

src/version.c

@@ -799,6 +799,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    635,
 /**/
     634,
 /**/