Remove duplicate declaration of allocator

Author: jeongsoolee09

cpp/common/test/includes/standard-library/memory.h

@@ -6,12 +6,6 @@
 
 namespace std {
 
-template <class T> class allocator {
-public:
-  allocator() throw();
-  typedef size_t size_type;
-};
-
 template <class T> T *addressof(T &arg) noexcept;
 
 template <typename T> struct default_delete {