Fix Monitor under current branch

Author: wuwbobo2021

java-spaghetti/src/refs/ref_.rs

@@ -197,11 +197,10 @@ impl<'env, T: ReferenceType> Drop for Monitor<'env, T> {
         let jnienv = env.as_raw();
         let result = unsafe { ((**jnienv).v1_2.MonitorExit)(jnienv, self.inner.as_raw()) };
         assert!(result == jni_sys::JNI_OK);
-        if let Err(exception) = env.exception_check_raw() {
-            panic!(
-                "exception happened calling JNI MonitorExit, the monitor is probably broken previously: {}",
-                unsafe { env.raw_exception_to_string(exception) }
-            );
-        }
+        let exception = unsafe { ((**jnienv).v1_2.ExceptionOccurred)(jnienv) };
+        assert!(
+            exception.is_null(),
+            "exception happened calling JNI MonitorExit, the monitor is probably broken previously"
+        );
     }
 }