* add op indicate var type method call check
* add error test example, test=develop, test=document_fix
* add count judge, test=develop, test=document_fix
* polish example detail, test=develop, test=document_fix
* test indicate var data type method, test=develop, test=document_fix
* test no get expect kernel type, test=develop, test=document_fix
* remove test case, test=develop test=document_fix
echo_line="If you override GetExpectedKernelType method of OperatorWithKernel, please use OperatorWithKernel::IndicateVarDataType() method to get specific input variable's dtype, which checked whether the input variable is initialized (The details in https://github.com/PaddlePaddle/FluidDoc/pull/1527). If you don't use this method to check, you must have one RD (chenwhql (Recommend) , luotao1 or lanxianghit) approval for the usage of other methods.\n"