Fix throw_catch_raise_catch test in old runtime

crates/tests/src/exception.rs

@@ -42,9 +42,13 @@ fn throw_catch_raise_catch() {
 
         let exc = NSException::from_exception(res.unwrap_err().unwrap()).unwrap();
 
-        // Undesired: The inner pool _should_ have been drained on unwind, but
-        // it isn't, see `rc::Pool::drain`.
-        assert_eq!(exc.retainCount(), 2);
+        if cfg!(all(target_os = "macos", target_arch = "x86")) {
+            assert_eq!(exc.retainCount(), 1);
+        } else {
+            // Undesired: The inner pool _should_ have been drained on unwind,
+            // but it isn't in newer runtimes, see docs on `rc::Pool::drain`.
+            assert_eq!(exc.retainCount(), 2);
+        }
         exc
     });