[Backport] 8230400: Missing constant pool entry for a method in stacktrace

Summary:

Test Plan: jdk/jfr

Reviewed-by: yuleil

Issue: https://github.com/alibaba/dragonwell8/issues/112

src/share/classes/jdk/jfr/internal/MetadataRepository.java

 /*
- * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -232,20 +232,22 @@ public final class MetadataRepository {
         staleMetadata = true;
     }
 
-    // Lock around setOutput ensures that other threads dosn't
-    // emit event after setOutput and unregister the event class, before a call
+    // Lock around setOutput ensures that other threads don't
+    // emit events after setOutput and unregister the event class, before a call
     // to storeDescriptorInJVM
     synchronized void setOutput(String filename) {
+        if (staleMetadata) {
+            storeDescriptorInJVM();
+        }
         jvm.setOutput(filename);
 
         unregisterUnloaded();
         if (unregistered) {
-            staleMetadata = typeLibrary.clearUnregistered();
-            unregistered = false;
-        }
-        if (staleMetadata) {
+            if (typeLibrary.clearUnregistered()) {
                 storeDescriptorInJVM();
             }
+            unregistered = false;
+        }
     }
 
     private void unregisterUnloaded() {