patch 8.2.4241: some type casts are redundant

Problem:    Some type casts are redundant.
Solution:   Remove the type casts. (closes #9643)
diff --git a/src/ex_eval.c b/src/ex_eval.c
index a48f609..ab30798 100644
--- a/src/ex_eval.c
+++ b/src/ex_eval.c
@@ -2283,7 +2283,7 @@
     {
 	if (pending & CSTP_THROW)
 	    // Cancel the pending exception (includes report).
-	    discard_exception((except_T *)csp->exception, FALSE);
+	    discard_exception(csp->exception, FALSE);
 	else
 	    report_discard_pending(pending, NULL);