analyzer: move bounds checking to a new bounds-checking.cc

analyzer: move bounds checking to a new bounds-checking.cc

gcc/ChangeLog:
	* Makefile.in (ANALYZER_OBJS): Add analyzer/bounds-checking.o.

gcc/analyzer/ChangeLog:
	* bounds-checking.cc: New file, taken from region-model.cc.
	* region-model.cc (class out_of_bounds): Move to
	bounds-checking.cc.
	(class past_the_end): Likewise.
	(class buffer_overflow): Likewise.
	(class buffer_overread): Likewise.
	(class buffer_underflow): Likewise.
	(class buffer_underread): Likewise.
	(class symbolic_past_the_end): Likewise.
	(class symbolic_buffer_overflow): Likewise.
	(class symbolic_buffer_overread): Likewise.
	(region_model::check_symbolic_bounds): Likewise.
	(maybe_get_integer_cst_tree): Likewise.
	(region_model::check_region_bounds): Likewise.
	* region-model.h: Add comment.

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