Update arm response types to match current Azure.Core pattern

eng/Packages.Data.props

@@ -127,7 +127,7 @@
     All should have PrivateAssets="All" set so they don't become pacakge dependencies
   -->
   <ItemGroup>
-    <PackageReference Update="Microsoft.Azure.AutoRest.CSharp" Version="3.0.0-beta.20210414.5" PrivateAssets="All" />
+    <PackageReference Update="Microsoft.Azure.AutoRest.CSharp" Version="3.0.0-beta.20210426.2" PrivateAssets="All" />
     <PackageReference Update="Azure.ClientSdk.Analyzers" Version="0.1.1-dev.20210322.2" PrivateAssets="All" />
     <PackageReference Update="coverlet.collector" Version="1.3.0" PrivateAssets="All" />
     <PackageReference Update="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="3.3.1" PrivateAssets="All" />

sdk/core/Azure.Core/tests/Azure.Core.Tests.csproj

@@ -4,6 +4,7 @@
     <TargetFrameworks>$(RequiredTargetFrameworks)</TargetFrameworks>
     <DefineConstants>$(DefineConstants);HAS_INTERNALS_VISIBLE_CORE</DefineConstants>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <IncludeGeneratorSharedCode>true</IncludeGeneratorSharedCode>
   </PropertyGroup>
 
   <ItemGroup>

sdk/core/Azure.Core/tests/TestClients/ArmOperationTest.cs

@@ -2,8 +2,11 @@
 // Licensed under the MIT License.
 
 using System;
+using System.Linq;
+using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
+using Azure.Core;
 using Azure.ResourceManager.Core;
 
 namespace Azure.Core.Tests
@@ -53,15 +56,15 @@ public override ValueTask<Response<T>> WaitForCompletionAsync(TimeSpan pollingIn
             return new ValueTask<Response<T>>(Response.FromValue(_value, null));
         }
 
-        public override ValueTask<Response> UpdateStatusAsync(CancellationToken cancellationToken = default)
+        public override T CreateResult(Response response, CancellationToken cancellationToken)
         {
             if (_exceptionOnWait)
                 throw new ArgumentException("FakeArg");
 
             return new ValueTask<Response>(Response.FromValue(_value, null) as Response);
         }
 
-        public override Response UpdateStatus(CancellationToken cancellationToken = default)
+        public async override ValueTask<T> CreateResultAsync(Response response, CancellationToken cancellationToken)
         {
             if (_exceptionOnWait)
                 throw new ArgumentException("FakeArg");