Fix the test framework for test. (#13803)

Author: kceiw

tools/Az.Tools.Predictor/build.proj

@@ -10,7 +10,7 @@
     <ModuleName>Az.Tools.Predictor</ModuleName>
     <ArtifactFolder>$(RepoArtifacts)Tools</ArtifactFolder>
     <ModuleSolutionFile>$(ModuleName).sln</ModuleSolutionFile>
-    <TestFramework>.Net5.0</TestFramework>
+    <TestFramework>Net5.0</TestFramework>
     <TestOutputDirectory>$(RepoArtifacts)/TestResults/$(ModuleName)</TestOutputDirectory>
   </PropertyGroup>