tokenize-symbol-thoroughly is incorrect under *print-case*=:invert

[kchanqvq]

> (swank::tokenize-symbol-thoroughly "cl-user:Test")
"tEST"
"CL-USER"
nil

This is incorrect, symbol-name of cl-user:Test is Test. *print-case*=:invert only invert the case if all characters are upper or lower case.

I'm looking at a way to fix tokenize-symbol-thoroughly. We can add the above test, or I wonder can we reuse the Lisp reader/printer and do something like

(defun convert-case (string)
  "Convert external representation of STRING into internal representation
for `package-name's and `symbol-name's."
  (let ((*print-case* :upcase))
    (format nil "~a" (make-symbol string))))
(defun unconvert-case (string)
  (let ((*print-case* :downcase))
    (format nil "~a" (make-symbol string))))

Maybe we can even replace the current logic that handles escape character and delegate to the Lisp reader/printer. Is this a good idea?