Add additional indirection to test

Author: Aaron1011

tests/run-pass/catch_panic.rs

@@ -41,7 +41,10 @@ fn main() {
     std::panic::set_hook(Box::new(|_panic_info| {
         HOOK_CALLED.with(|h| h.set(true));
     }));
-    let res = catch_unwind(do_panic_counter);
+    let res = catch_unwind(|| {
+        let _string = "LEAKED FROM CLOSURE".to_string();
+        do_panic_counter()
+    });
     let expected: Box<String> = Box::new("Hello from panic: 0".to_string());
     let actual = res.expect_err("do_panic() did not panic!")
         .downcast::<String>().expect("Failed to cast to string!");