patch 8.2.1311: test failures with legacy Vim script

Problem:    Test failures with legacy Vim script.
Solution:   Actually check for Vim9 script.

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1311,
 /**/
     1310,
 /**/

src/vim9script.c

@@ -64,6 +64,7 @@ ex_vim9script(exarg_T *eap)
     int
 not_in_vim9(exarg_T *eap)
 {
+    if (in_vim9script())
 	switch (eap->cmdidx)
 	{
 	    case CMD_insert: