XWIKI-11565: Wiki descriptors retrieved from the cache are the internal references

* so much for writing unit tests

xwiki-platform-core/xwiki-platform-wiki/xwiki-platform-wiki-api/src/main/java/org/xwiki/wiki/descriptor/WikiDescriptor.java

@@ -300,7 +300,7 @@ public WikiDescriptor clone()
         // Clone properties
         descriptor.propertyGroups = new HashMap<>(this.propertyGroups.size());
         for (WikiPropertyGroup group : this.propertyGroups.values()) {
-            propertyGroups.put(group.getId(), group.clone());
+            descriptor.propertyGroups.put(group.getId(), group.clone());
         }
 
         return descriptor;

xwiki-platform-core/xwiki-platform-wiki/xwiki-platform-wiki-default/src/test/java/org/xwiki/wiki/internal/descriptor/DefaultWikiDescriptorManagerTest.java

@@ -269,6 +269,7 @@ public void getMainWikiDescriptor() throws Exception
         assertEquals(descriptor, this.mocker.getComponentUnderTest().getMainWikiDescriptor());
     }
 
+    @Test
     public void testCacheProtection() throws WikiManagerException, ComponentLookupException
     {
         DefaultWikiDescriptor descriptor = new DefaultWikiDescriptor("xwiki", "xwiki");