tsm decay: try to work around some more removal bugs

BizHawk.Client.Common/movie/tasproj/StateManagerDecay.cs

@@ -156,6 +156,8 @@ namespace BizHawk.Client.Common
 						backwardFrame = currentFrame;
 					}
 				}
+				
+				int decayStatesLast = decayStates;
 
 				if (forwardFrame > -1 && backwardFrame > -1)
 				{
@@ -192,10 +194,11 @@ namespace BizHawk.Client.Common
 						decayStates--;
 					}
 				}
-				else
-				{
+				
 				// we're very sorry about failing to find states to remove, but we can't go beyond capacity, so remove at least something
 				// this shouldn't happen, but if we don't do it here, nothing good will happen either
+				if (decayStatesLast == decayStates)
+				{
 					if (_tsm.RemoveState(_tsm.GetStateFrameByIndex(1)))
 					{
 						// decrementing this if no state was removed is BAD