Everywhere: Turn #if *_DEBUG into dbgln_if/if constexpr

Author: https://github.com/gunnarbeutner
Commit: 6cf59b6ae9
Pull-request: https://github.com/SerenityOS/serenity/pull/6796

Userland/Libraries/LibCore/EventLoop.cpp

@@ -393,9 +393,7 @@ void EventLoop::pump(WaitMode mode)
                 break;
             }
         } else if (event.type() == Event::Type::DeferredInvoke) {
-#if DEFERRED_INVOKE_DEBUG
-            dbgln("DeferredInvoke: receiver = {}", *receiver);
-#endif
+            dbgln_if(DEFERRED_INVOKE_DEBUG, "DeferredInvoke: receiver = {}", *receiver);
             static_cast<DeferredInvocationEvent&>(event).m_invokee(*receiver);
         } else {
             NonnullRefPtr<Object> protector(*receiver);