event.test: try to silence test event 12.1

github actions produces some spurious output for this test.
Write it in v2 style without catch

Signed-off-by: Steve Bennett <steveb@workware.net.au>

tests/event.test

@@ -170,9 +170,10 @@ test event-11.6 {Tcl_VwaitCmd procedure: round robin scheduling, same source} {s
     list $x $y $z
 } {3 3 done}
 
-test event-12.1 {Tcl_UpdateCmd procedure} {
-    list [catch {update a b} msg] $msg
-} {1 {wrong # args: should be "update ?idletasks?"}}
+test event-12.1 {Tcl_UpdateCmd procedure - usage} -body {
+    update a b
+} -returnCodes error -result {wrong # args: should be "update ?idletasks?"}
+
 test event-12.3 {Tcl_UpdateCmd procedure} {
     foreach i [after info] {
 	after cancel $i