analyzer: fix missing uninit warning on args to stdio builtins [PR104224]

analyzer: fix missing uninit warning on args to stdio builtins [PR104224]

We were failing to check for uninitialized arguments to stdio builtins,
such as when passing local "go" to the call to "printf" in "main" in
the testcase.

gcc/analyzer/ChangeLog:
	PR analyzer/104224
	* region-model.cc (region_model::check_call_args): New.
	(region_model::on_call_pre): Call it when ignoring stdio builtins.
	* region-model.h (region_model::check_call_args): New decl

gcc/testsuite/ChangeLog:
	PR analyzer/104224
	* gcc.dg/analyzer/pr104224.c: New test.

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