Make Monster's Color unsigned (#5318)

- update C++ monster_test::Color to unsigned type
- update Go Color:ubyte in the go_test.go
- add workaround for unsigned enum in java test
- sync generate.bat and generate.sh

tests/MyGame/Example/Color.go

@@ -2,7 +2,7 @@
 
 package Example
 
-type Color = int8
+type Color = byte
 const (
 	ColorRed Color = 1
 	ColorGreen Color = 2