[Android] Give the exceptions in compareTo implementations in GameLis…

…tItem and FolderBrowserItem some messages. If the exceptions ever actually get thrown, at least you're given a reason as to why the exception was thrown now. Also changed the exception type to NullPointerException. IllegalArgumentException is intended to be used for validating the parameters in constructors/methods.

Source/Android/src/org/dolphinemu/dolphinemu/folderbrowser/FolderBrowserItem.java

@@ -104,6 +104,6 @@ public int compareTo(FolderBrowserItem other)
 		if(name != null)
 			return name.toLowerCase().compareTo(other.getName().toLowerCase()); 
 		else 
-			throw new IllegalArgumentException();
+			throw new NullPointerException("The name of this FolderBrowserItem is null");
 	}
 }

Source/Android/src/org/dolphinemu/dolphinemu/gamelist/GameListItem.java

@@ -117,7 +117,7 @@ public int compareTo(GameListItem o)
 		if (name != null)
 			return name.toLowerCase().compareTo(o.getName().toLowerCase()); 
 		else 
-			throw new IllegalArgumentException();
+			throw new NullPointerException("The name of this GameListItem is null");
 	}
 }