analyzer: don't track string literals in the store [PR106359]

analyzer: don't track string literals in the store [PR106359]

Doing so speeds up -fanalyzer from taking over 4 hours to under a
minute on the Linux kernel's sound/soc/codecs/cs47l90.c

gcc/analyzer/ChangeLog:
	PR analyzer/106359
	* region.h (string_region::tracked_p): New.
	* store.cc (binding_cluster::binding_cluster): Move here from
	store.h.  Add assertion that base_region is tracked_p.
	* store.h (binding_cluster::binding_cluster): Move to store.cc.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>