Bank surface source particles in all active cycles (#2592)

Co-authored-by: Jose Ignacio Marquez Damian <22483345+marquezj@users.noreply.github.com>

include/openmc/shared_array.h

@@ -107,6 +107,9 @@ public:
   //! \param size The new size of the container
   void resize(int64_t size) { size_ = size; }
 
+  //! Return whether the array is full
+  bool full() const { return size_ == capacity_; }
+
   //! Return the number of elements that the container has currently allocated
   //! space for.
   int64_t capacity() { return capacity_; }