Don't reparse the sexp in indent-sexp (Bug#25122)
* lisp/emacs-lisp/lisp-mode.el (calculate-lisp-indent): Let
PARSE-START be a parse state that can be reused.
(indent-sexp): Pass the running parse state to calculate-lisp-indent
instead of the sexp beginning position. Saving the
CONTAINING-SEXP-START returned by `calculate-lisp-indent' is no longer
needed. Don't bother stopping if we don't descend below init-depth,
since we now alway scan the whole buffer (via syntax-ppss) anyway.
* test/lisp/emacs-lisp/lisp-mode-tests.el (indent-sexp): Add blank
line to test case.