Make reload button clear the network cache.

components/constellation/constellation.rs

@@ -1529,6 +1529,10 @@ where
                     },
                 };
             },
+            FromCompositorMsg::ClearCache => {
+                self.public_resource_threads.clear_cache();
+                self.private_resource_threads.clear_cache();
+            },
             // Load a new page from a typed url
             // If there is already a pending page (self.pending_changes), it will not be overridden;
             // However, if the id is not encompassed by another change, it will be.