analyzer: don't call binding_key::make on empty regions [PR108065]

analyzer: don't call binding_key::make on empty regions [PR108065]

gcc/analyzer/ChangeLog:
	PR analyzer/108065
	* region.cc (decl_region::get_svalue_for_initializer): Bail out to
	avoid calling binding_key::make with an empty region.
	* store.cc (binding_map::apply_ctor_val_to_range): Likewise.
	(binding_map::apply_ctor_pair_to_child_region): Likewise.
	(binding_cluster::bind): Likewise.
	(binding_cluster::purge_region): Likewise.
	(binding_cluster::maybe_get_compound_binding): Likewise.
	(binding_cluster::maybe_get_simple_value): Likewise.

gcc/testsuite/ChangeLog:
	PR analyzer/108065
	* gfortran.dg/analyzer/pr108065.f90: New test.

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