analyzer: fix false leak reports when merging states [PR97074]

analyzer: fix false leak reports when merging states [PR97074]

gcc/analyzer/ChangeLog:
	PR analyzer/97074
	* store.cc (binding_cluster::can_merge_p): Add "out_store" param
	and pass to calls to binding_cluster::make_unknown_relative_to.
	(binding_cluster::make_unknown_relative_to): Add "out_store"
	param.  Use it to mark base regions that are pointed to by
	pointers that become unknown as having escaped.
	(store::can_merge_p): Pass out_store to
	binding_cluster::can_merge_p.
	* store.h (binding_cluster::can_merge_p): Add "out_store" param.
	(binding_cluster::make_unknown_relative_to): Likewise.
	* svalue.cc (region_svalue::implicitly_live_p): New vfunc.
	* svalue.h (region_svalue::implicitly_live_p): New vfunc decl.

gcc/testsuite/ChangeLog:
	PR analyzer/97074
	* gcc.dg/analyzer/pr97074.c: New test.