Remove redundant sleep in RamCachingFileLoader

Core/FileLoaders/RamCachingFileLoader.cpp

@@ -104,12 +104,11 @@ void RamCachingFileLoader::ShutdownCache() {
 
 	// We can't delete while the thread is running, so have to wait.
 	// This should only happen from the menu.
-	while (aheadThreadRunning_) {
-		sleep_ms(1, "shutdown-ram-cache-poll");
-	}
 	if (aheadThread_.joinable())
 		aheadThread_.join();
 
+	_dbg_assert_(!aheadThreadRunning_);
+
 	std::lock_guard<std::mutex> guard(blocksMutex_);
 	blocks_.clear();
 	if (cache_ != nullptr) {