Change the length of the npn4arr array.
In the execution this resizes (to grow or shrink) the underlying Common Lisp array. The logical definition is based on resize-list:
Function:
(defun resize-npn4s$a (stobjs::i npn4arr$a) (declare (xargs :guard (npn4arr$ap npn4arr$a))) (resize-list npn4arr$a stobjs::i '0))