Fix memory leak in JDWP object registry

Deletes ObjectRegistryEntry objects before clearing the maps.

Change-Id: Iaa30941fb8768b7294366a8f9855580cb29dadf5
diff --git a/runtime/jdwp/object_registry.cc b/runtime/jdwp/object_registry.cc
index d637a94..29d3c8a 100644
--- a/runtime/jdwp/object_registry.cc
+++ b/runtime/jdwp/object_registry.cc
@@ -115,12 +115,13 @@
   // Delete all the JNI references.
   JNIEnv* env = self->GetJniEnv();
   for (const auto& pair : object_to_entry_) {
-    const ObjectRegistryEntry& entry = *pair.second;
-    if (entry.jni_reference_type == JNIWeakGlobalRefType) {
-      env->DeleteWeakGlobalRef(entry.jni_reference);
+    const ObjectRegistryEntry* entry = pair.second;
+    if (entry->jni_reference_type == JNIWeakGlobalRefType) {
+      env->DeleteWeakGlobalRef(entry->jni_reference);
     } else {
-      env->DeleteGlobalRef(entry.jni_reference);
+      env->DeleteGlobalRef(entry->jni_reference);
     }
+    delete entry;
   }
   // Clear the maps.
   object_to_entry_.clear();