tree-object-size.c (pass_through_call): Use gimple_call_return_flags ERF_RETURN*ARG* for builtins other than...

	* tree-object-size.c (pass_through_call): Use gimple_call_return_flags
	ERF_RETURN*ARG* for builtins other than BUILT_IN_ASSUME_ALIGNED,
	check for the latter with gimple_call_builtin_p.  Do not handle
	BUILT_IN_STPNCPY_CHK which is not a pass through call.

	* gcc.dg/builtin-object-size-18.c: New test.

From-SVN: r255133