Fix run-pass tests

src/test/run-pass/issues/issue-30530.rs

@@ -12,7 +12,9 @@ pub enum Handler {
 }
 
 fn main() {
-    take(Handler::Default, Box::new(main));
+    #[allow(unused_must_use)] {
+        take(Handler::Default, Box::new(main));
+    }
 }
 
 #[inline(never)]

src/test/run-pass/panics/panic-handler-flail-wildly.rs

@@ -1,5 +1,7 @@
 // run-pass
+
 #![allow(stable_features)]
+#![allow(unused_must_use)]
 
 // ignore-emscripten no threads support