* lisp/emacs-lisp/byte-opt.el (byte-compile-trueconstp): Extend

* lisp/emacs-lisp/byte-opt.el (byte-compile-trueconstp): Extend

Add skip-chars-forward, skip-chars-backward, skip-syntax-forward,
skip-syntax-backward, current-column, current-indentation,
char-syntax, syntax-class-to-char, parse-partial-sexp, goto-char,
forward-line, next-window, previous-window, minibuffer-window,
selected-frame, selected-window, standard-case-table,
standard-syntax-table, syntax-table, frame-first-window,
frame-root-window and frame-selected-window as always-true functions.