Fixed failing test cases

While working locally, the test were not working on the CI job. this
appeared to be due to issues with path for the model, as well as not
using OnnxFact.

test/Microsoft.ML.Tests/OnnxSequenceTypeWithAttributesTest.cs

@@ -12,6 +12,7 @@
 using Xunit.Abstractions;
 using System.Linq;
 using System.IO;
+using Microsoft.ML.TestFramework.Attributes;
 
 namespace Microsoft.ML.Tests
 {
@@ -46,10 +47,10 @@ public static PredictionEngine<FloatInput, OutputObj> LoadModel(string onnxModel
             return ctx.Model.CreatePredictionEngine<FloatInput, OutputObj>(model);
         }
 
-        [Fact]
+        [OnnxFact]
         public void OnnxSequenceTypeWithColumnNameAttributeTest()
         {
-            var modelFile = @"zipmap/TestZipMapString.onnx";
+            var modelFile = Path.Combine(Directory.GetCurrentDirectory(), "zipmap", "TestZipMapString.onnx");
             var predictor = LoadModel(modelFile);
 
             FloatInput input = new FloatInput() { Input = new float[] { 1.0f, 2.0f, 3.0f } };