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,