tests: fix memory leak report by valgrind
tests: fix memory leak report by valgrind

	transform destructor of EncodeInput to virtual function, otherwise its derived class
can't release correctly

seanvk/libyami,chivakker/libyami,dspmeng/libyami,zhongcong/libyami,YuJiankang/libyami,YuJiankang/libyami,yizhouwei/libyami,seanvk/libyami,andyLiuChina/libyami,uartie/libyami,BtbN/libyami,lizhong1008/libyami,stripes416/libyami,andyLiuChina/libyami,wlin70/libyami,halleyzhao/libyami,wlin70/libyami,xuguangxin/libyami,wlin70/libyami,dspmeng/libyami,01org/libyami,halleyzhao/libyami,zhaobob/libyami,yizhouwei/libyami,bluceldg/libyami,bluceldg/libyami,seanvk/libyami,chivakker/libyami,uartie/libyami,lizhong1008/libyami,chivakker/libyami,clearlylin/libyami,uartie/libyami,BtbN/libyami,YuJiankang/libyami,wlin70/libyami,bluceldg/libyami,dspmeng/libyami,yizhouwei/libyami,xuguangxin/libyami,stripes416/libyami,lizhong1008/libyami,zhongcong/libyami,zhongcong/libyami,BtbN/libyami,01org/libyami,xuguangxin/libyami,zhaobob/libyami,clearlylin/libyami,BtbN/libyami,bluceldg/libyami,andyLiuChina/libyami,zhongcong/libyami,andyLiuChina/libyami,zhaobob/libyami,xuguangxin/libyami,01org/libyami,halleyzhao/libyami,halleyzhao/libyami,clearlylin/libyami,stripes416/libyami