[test] Fix test for skipped target

Author: rmarinho

src/Controls/tests/Xaml.UnitTests/MSBuild/MSBuildTests.cs

@@ -495,7 +495,7 @@ public void NoXamlFiles()
 			var projectFile = IOPath.Combine(tempDirectory, "test.csproj");
 			project.Save(projectFile);
 			var log = Build(projectFile, verbosity: "diagnostic");
-			Assert.IsTrue(log.Contains("Target \"XamlC\" skipped", StringComparison.Ordinal), "XamlC should be skipped if there are no .xaml files.");
+			Assert.IsFalse(log.Contains("Building target \"XamlC\"", StringComparison.Ordinal), "XamlC should be skipped if there are no .xaml files.");
 		}
 	}
 }