CC Mode: Optimize font-locking stanzas for long raw strings.

CC Mode: Optimize font-locking stanzas for long raw strings.

Also replace some regexp searches which had caused regexp engine stack
overflows with simple end-of-line calls.

* lisp/progmodes/cc-fonts.el (c-make-syntactic-matcher)
(c-make-font-lock-search-form): Start the generated functions with a skipping
of comments and strings.
(c-make-font-lock-BO-decl-search-function): Start the generated function with
a (fast) movement to the start of any literal.

* lisp/progmodes/cc-mode.el (c-before-change-check-unbalanced-strings)
(c-after-change-mark-abnormal-strings): Replace complicated regexp searches
for end of logical line with basic Lisp functions.