added extra coverage to unknown test

test/onnx/onnx_test.cpp

@@ -334,6 +334,7 @@ void unknown_test()
     auto l0 = p.add_parameter("0", migraphx::shape{migraphx::shape::float_type, {2, 3, 4, 5}});
     auto l1 = p.add_parameter("1", migraphx::shape{migraphx::shape::float_type, {3, 4}});
     p.add_instruction(migraphx::unknown{"Unknown"}, l0, l1);
+    p.add_instruction(migraphx::unknown{"Unknown"});
     auto prog = migraphx::parse_onnx("unknown_test.onnx");
 
     EXPECT(p == prog);

test/onnx/unknown_test.onnx

-unknown-example:q
+unknown-example:|
 
 
0
-
1
2"Unknowntest-unknownZ
+
1
2"Unknown
+	"Unknowntest-unknownZ
 
0