3DS: Reduce autosave thread stack size

It was unnecessarily large and seemed to sometimes trigger an edge case in
newlib's heap handling, leading to an infinite loop when trying to merge
heap bins. It seems to be a super-specific edge-case of when these bins
merge, so it's really hard to tell if it is a newlib bug or not.

Author: endrift

src/platform/3ds/main.c

@@ -1066,7 +1066,7 @@ int main(int argc, char* argv[]) {
 	ConditionInit(&runner.autosave.cond);
 
 	APT_SetAppCpuTimeLimit(20);
-	runner.autosave.thread = threadCreate(mGUIAutosaveThread, &runner.autosave, 0x4000, 0x1F, 1, true);
+	runner.autosave.thread = threadCreate(mGUIAutosaveThread, &runner.autosave, 0x2000, 0x1F, 1, true);
 
 	Thread thread2;
 	if (ThreadCreate(&thread2, _core2Test, NULL) == 0) {