Force-enable coprocessor delayed-sync while creating a save-state.

When making a save state, all the system components are "fast forwarded" to a
safe state that can be serialised. If delayedSync (called "Coprocessor Fast
Sync" in the UI) is enabled, this works perfectly. If it is disabled, the
accurate coprocessor synching interferes with the save-state creation, leading
to the game crashing or (worse) the emulator freezing.

Star Fox is a good test case - repeatedly saving state and loading it will very
quickly cause the game to run super-slowly, hang, or crash.

Ideally, somebody should dig into exactly what coprocessor syncing is doing
that breaks the assumptions of the state-saving code, but given how complex
the whole thing is, and given that it doesn't affect hardware emulation
accuracy (real hardware can't save states at all), it's easiest to just force-
enable delayedSync while a save-state is in progress.

Fix from the jgemu bsnes fork:
8b4d1b8ae5

bsnes/sfc/system/system.cpp

@@ -15,6 +15,12 @@ auto System::run() -> void {
 }
 
 auto System::runToSave() -> void {
+  // Enable coprocessor delayed sync if it is off - this is extremely important
+  // for coprocessor games, as many will not sync correctly for states when the
+  // option is off.
+  bool delay_sync_prev = configuration.hacks.coprocessor.delayedSync;
+  configuration.hacks.coprocessor.delayedSync = true;
+
   auto method = configuration.system.serialization.method;
 
   //these games will periodically deadlock when using "Fast" synchronization
@@ -30,6 +36,9 @@ auto System::runToSave() -> void {
 
   scheduler.mode = Scheduler::Mode::Run;
   scheduler.active = cpu.thread;
+
+  // Restore coprocessor delayed sync to whatever it was previous to the state save operation
+  configuration.hacks.coprocessor.delayedSync = delay_sync_prev;
 }
 
 auto System::runToSaveFast() -> void {