analyzer: move svalue and region decls to their own header files

analyzer: move svalue and region decls to their own header files

gcc/ChangeLog:
	* Makefile.in (ANALYZER_OBJS): Add analyzer/complexity.o.

gcc/analyzer/ChangeLog:
	* analyzer.h (class state_machine): New forward decl.
	(class logger): Likewise.
	(class visitor): Likewise.
	* complexity.cc: New file, taken from svalue.cc.
	* complexity.h: New file, taken from region-model.h.
	* region-model.h: Include "analyzer/svalue.h" and
	"analyzer/region.h".  Move struct complexity to complexity.h.
	Move svalue, its subclasses and supporting decls to svalue.h.
	Move region, its subclasses and supporting decls to region.h.
	* region.cc: Include "analyzer/region.h".
	(symbolic_region::symbolic_region): Move here from region-model.h.
	* region.h: New file, based on material from region-model.h.
	* svalue.cc: Include "analyzer/svalue.h".
	(complexity::complexity): Move to complexity.cc.
	(complexity::from_pair): Likewise.
	* svalue.h: New file, based on material from region-model.h.