Fix an infinite loop in c-end-of-macro. Should fix bug #36484

Fix an infinite loop in c-end-of-macro.  Should fix bug #36484

Also fix two faulty regexps, save-match-data, and check c-major-mode-is
'c++-mode where needed.

* lis/progmodes/cc-langs.el (c-last-c-comment-end-on-line-re)
(c-last-open-c-comment-start-on-line-re): Handle repeated *s in regexp
correctly.

* lisp/progmodes/cc-engine.el (c-beginning-of-macro, c-end-of-macro): Protect
the match-data with save-match-data around regexp operations.
(c-end-of-macro): In the loop handling multiline block comments, check a
comment actually is multiline.

* lisp/progmodes/cc-mode.el (c-depropertize-CPP): Only call
c-depropertize-raw-strings-in-region in C++ Mode.