unsubscribe from events in core Dispose methods

- closes #4157

Not sure this is the best way to fix the linked issue, but considering this is a hard crash I'd rather fix it somehow than not at all for now.

src/BizHawk.Emulation.Cores/Calculators/Emu83/Emu83.IEmulator.cs

@@ -41,6 +41,7 @@ namespace BizHawk.Emulation.Cores.Calculators.Emu83
 
 		public void Dispose()
 		{
+			_memoryCallbacks.ActiveChanged -= SetMemoryCallbacks;
 			if (Context != IntPtr.Zero)
 			{
 				LibEmu83.TI83_DestroyContext(Context);

src/BizHawk.Emulation.Cores/Consoles/Atari/jaguar/VirtualJaguar.cs

@@ -300,5 +300,11 @@ namespace BizHawk.Emulation.Cores.Atari.Jaguar
 			Marshal.Copy(_buf2352, 0, dst, 2352);
 			DriveLightOn = true;
 		}
+
+		public override void Dispose()
+		{
+			_memoryCallbacks.ActiveChanged -= SetMemoryCallbacks;
+			base.Dispose();
+		}
 	}
 }

src/BizHawk.Emulation.Cores/Consoles/Nintendo/Gameboy/Gambatte.IEmulator.cs

@@ -163,6 +163,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.Gameboy
 
 		public void Dispose()
 		{
+			_memorycallbacks.ActiveChanged -= SetMemoryCallbacks;
 			if (GambatteState != IntPtr.Zero)
 			{
 				LibGambatte.gambatte_destroy(GambatteState);

src/BizHawk.Emulation.Cores/Consoles/Nintendo/NDS/MelonDS.cs

@@ -539,6 +539,8 @@ namespace BizHawk.Emulation.Cores.Consoles.Nintendo.NDS
 				_glContext = null;
 			}
 
+			_memoryCallbacks.ActiveChanged -= SetMemoryCallbacks;
+
 			base.Dispose();
 		}
 

src/BizHawk.Emulation.Cores/Consoles/Nintendo/SameBoy/SameBoy.IEmulator.cs

@@ -156,6 +156,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.Sameboy
 
 		public void Dispose()
 		{
+			_memorycallbacks.ActiveChanged -= SetMemoryCallbacks;
 			if (SameboyState != IntPtr.Zero)
 			{
 				LibSameboy.sameboy_destroy(SameboyState);

src/BizHawk.Emulation.Cores/Consoles/Sega/gpgx64/GPGX.IEmulator.cs

@@ -122,6 +122,7 @@ namespace BizHawk.Emulation.Cores.Consoles.Sega.gpgx
 		{
 			if (!_disposed)
 			{
+				_memoryCallbacks.ActiveChanged -= RefreshMemCallbacks;
 				_elf?.Dispose();
 
 				if (_cds != null)

src/BizHawk.Emulation.Cores/Consoles/Sony/PSX/Octoshock.cs

@@ -348,6 +348,8 @@ namespace BizHawk.Emulation.Cores.Sony.PSX
 
 			disposed = true;
 
+			_memoryCallbacks.ActiveChanged -= RefreshMemCallbacks;
+
 			//discs arent bound to shock core instances, but they may be mounted. kill the core instance first to effectively dereference the disc
 			OctoshockDll.shock_Destroy(psx);
 			psx = IntPtr.Zero;

src/BizHawk.Emulation.Cores/Consoles/WonderSwan/WonderSwan.cs

@@ -52,6 +52,8 @@ namespace BizHawk.Emulation.Cores.WonderSwan
 
 		public void Dispose()
 		{
+			_inputCallbacks.ActiveChanged -= SetInputCallback;
+			_memorycallbacks.ActiveChanged -= SetMemoryCallbacks;
 			if (Core != IntPtr.Zero)
 			{
 				BizSwan.bizswan_delete(Core);