bug#27779: 26.0.50: read -- Re-entering top level after C stack overflow

[Keith David Bershatsky]

Perhaps we can use a prior function written by @npostavs -- (make-deep-object 
DEPTH) -- to create a large enough example of nested vectors and lists such 
that someone on the Emacs development team can duplicate the C stack overflow 
with `read`:

    (require 'cl-lib)

    (defun make-deep-object (depth)
      (let ((obj 1))
        (while (> (cl-decf depth) 0)
          (setq obj (vector (list obj))))
        obj))