analyzer: fix false +ve buffer overflow on sprintf [PR117369]

analyzer: fix false +ve buffer overflow on sprintf [PR117369]

gcc/analyzer/ChangeLog:
	PR analyzer/117369
	* kf.cc (kf_sprintf::impl_call_pre): Use the capacity of the
	region when "faking" a write to the destination buffer, to
	avoid buffer overflow false +ves.

gcc/testsuite/ChangeLog:
	PR analyzer/117369
	* c-c++-common/analyzer/sprintf-pr117369.c: New test.
	* gcc.dg/analyzer/doom-d_main-IdentifyVersion.c: Update expected
	results to reflect complexity limits being hit earlier.

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