Publish testframework in nightly build (Azure#49182)

* Publish testframework in nightly build

* skiprelease

Author: JoshLove-msft

sdk/core/Azure.Core.TestFramework/src/Azure.Core.TestFramework.csproj

@@ -2,6 +2,7 @@
   <PropertyGroup>
     <TargetFrameworks>$(RequiredTargetFrameworks);net47</TargetFrameworks>
     <IncludeOperationsSharedSource>true</IncludeOperationsSharedSource>
+    <IsPackable>true</IsPackable>
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="Azure.Core" />

sdk/core/ci.yml

@@ -60,6 +60,9 @@ extends:
       safeName: AzureCoreAmqp
     - name: System.ClientModel
       safeName: SystemClientModel
+    - name: Azure.Core.TestFramework
+      safeName: AzureCoreTestFramework
+      skipReleaseStage: true
     CheckAOTCompat: true
     AOTTestInputs:
     - ArtifactName: Azure.Core