Dangling pointer bug in paddle/fluid/framework/executor.cc

[sneaxiy]

In the implementation of void Executor::Run(const ProgramDesc& program, Scope* scope, std::map<std::string, const LoDTensor*>* feed_targets, std::map<std::string, LoDTensor*>* fetch_targets, bool create_local_scope, bool create_vars, const std::string& feed_holder_name, const std::string& fetch_holder_name), when has_feed_ops or has_fetch_ops is false, a temporary unique_ptr object is created and the pointer it holds is assigned to copy_program. Thus, copy_program is a dangling pointer after the temporary object unique_ptr is destructed.