adjustable-array-p array ⇒  generalized-boolean
| array | an array. | 
| generalized-boolean | a generalized boolean. | 
Returns true if and only if adjust-array could return a value which is identical to array when given that array as its first argument.
 (adjustable-array-p 
   (make-array 5
               :element-type 'character 
               :adjustable t 
               :fill-pointer 3)) ⇒  true
 (adjustable-array-p (make-array 4)) ⇒  implementation-dependent
Should signal an error of type type-error if its argument is not an array.