CC Mode: truncate the semi-nonlit cache when applying syntax-table to a quote

CC Mode: truncate the semi-nonlit cache when applying syntax-table to a quote

This applies to applying or removing syntax-table text properties in raw
strings which affect the stringiness of a piece of text.  This fixes the
bug
reported in
http://lists.gnu.org/archive/html/emacs-devel/2016-06/msg00695.html.

* lisp/progmodes/cc-engine.el (c-truncate-semi-nonlit-pos-cache): new
defsubst.
(c-invalidate-state-cache-1): Call new function in place of inline
manipulation.
(c-depropertize-raw-string, c-propertize-raw-string-opener): truncate the
semi-nonlit cache when pertinent syntax-table text properties get applied to
the text.