Dialog: Prevent reschedule on shutdown start.

This is a bit strange, but tests seem to suggest this is correct.
A worse priority thread won't run before savedata shutdown hits 0, but the
thread that initiated shutdown runs before shutdown completes.

Fixes Freakout Extreme Freeride loading savedata.

Core/HLE/sceKernelThread.cpp

@@ -2063,7 +2063,8 @@ int __KernelStartThread(SceUID threadToStartID, int argSize, u32 argBlockPtr, bo
 			Core_ExecException(startThread->context.pc, currentMIPS->pc, ExecExceptionType::THREAD);
 		}
 		__KernelChangeReadyState(cur, currentThread, true);
-		hleReSchedule("thread started");
+		if (__InterruptsEnabled())
+			hleReSchedule("thread started");
 	}
 
 	// Starting a thread automatically resumes the dispatch thread if the new thread has worse priority.