Material system: leftover portal data after level change

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If I load the map test-portals and then load parpax (which doesn't have any portals) after, I get a log of Bad surface tesselated. warnings. It comes from here https://github.com/DaemonEngine/Daemon/blob/7ba945cb1938967f1c4aba77d02638c2eb5364d4/src/engine/renderer/tr_main.cpp#L2134