patch 8.2.0768: Vim9: memory leak in script test

Problem:    Vim9: memory leak in script test.
Solution:   Clear typval before giving an error message.
diff --git a/src/version.c b/src/version.c
index 7d351a0..8c89761 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    768,
+/**/
     767,
 /**/
     766,
diff --git a/src/vim9execute.c b/src/vim9execute.c
index 398c94c..c910dbc 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -1169,12 +1169,12 @@
 			n = tv->vval.v_number;
 		    msg = set_option_value(iptr->isn_arg.storeopt.so_name,
 					n, s, iptr->isn_arg.storeopt.so_flags);
+		    clear_tv(tv);
 		    if (msg != NULL)
 		    {
 			emsg(_(msg));
 			goto failed;
 		    }
-		    clear_tv(tv);
 		}
 		break;