analyzer: handle &STRING_CST in constant pool initializers [PR96642]

analyzer: handle &STRING_CST in constant pool initializers [PR96642]

In r11-2708-g2867118ddda9b56d991c16022f7d3d634ed08313 I added support to
the analyzer for initialization from var_decls in the global constant
pool.  However, that commit didn't support initialization from
ADDR_EXPR of a STRING_CST leading to an ICE seen in data-model-1.c and
pr94639.c on arm and powerpc64 at least, and as PR analyzer/96642 on
x86_64 at least.

This patch adds support for such initializers, fixing the ICE.

gcc/analyzer/ChangeLog:
	PR analyzer/96642
	* store.cc (get_svalue_for_ctor_val): New.
	(binding_map::apply_ctor_to_region): Call it.

gcc/testsuite/ChangeLog:
	PR analyzer/96642
	* gcc.dg/analyzer/pr96642.c: New test.