perl-mode.el: Improve indent after hanging open-paren

perl-mode.el: Improve indent after hanging open-paren

Make the indentation of the code right after an open paren/brace
use the same rule as already used to indent the corresponding
matching paren/brace.

* lisp/progmodes/perl-mode.el (perl-calculate-indent):
Use `perl-indent-new-calculate`s "virtual" indentation instead of
approximating it with `current-indentation`.

(cherry picked from commit bd86a6c4fde1aa42ea9e8b5434f0cb63f8d52684)