ISO: Fix loading games in continuous mode

Some games will load into another game and continuous mode will be set.
Currently, if this happens the ISO will get unloaded in the shutdown
function. This commit adds an additional check before calling the unload
function to fix this.

rpcs3/Emu/System.cpp

@@ -3886,7 +3886,6 @@ void Emulator::Kill(bool allow_autoexit, bool savestate, savestate_stage* save_s
 			disc.clear();
 			klic.clear();
 			hdd1.clear();
-			unload_iso();
 			init_mem_containers = nullptr;
 			m_config_path.clear();
 			m_config_mode = cfg_mode::custom;
@@ -3896,6 +3895,11 @@ void Emulator::Kill(bool allow_autoexit, bool savestate, savestate_stage* save_s
 			m_emu_state_close_pending = false;
 			m_precompilation_option = {};
 
+			if (!m_continuous_mode)
+			{
+				unload_iso();
+			}
+
 			initialize_timebased_time(0, true);
 
 			// Complete the operation