Update dependencies from https://github.com/dotnet/arcade build 20191001.4 (#38996)

- Microsoft.DotNet.Arcade.Sdk - 5.0.0-beta.19501.4

eng/Version.Details.xml

@@ -3,9 +3,9 @@
   <ProductDependencies>
   </ProductDependencies>
   <ToolsetDependencies>
-    <Dependency Name="Microsoft.DotNet.Arcade.Sdk" Version="5.0.0-beta.19480.3">
+    <Dependency Name="Microsoft.DotNet.Arcade.Sdk" Version="5.0.0-beta.19501.4">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>238f1bbb23ba67616818d0b242c5b55a18edec55</Sha>
+      <Sha>c21a409f11386d22c6083198176868d3974de832</Sha>
     </Dependency>
   </ToolsetDependencies>
 </Dependencies>

eng/common/tools.sh

@@ -332,7 +332,7 @@ function MSBuild {
     # Work around issues with Azure Artifacts credential provider
     # https://github.com/dotnet/arcade/issues/3932
     if [[ "$ci" == true ]]; then
-      dotnet nuget locals http-cache -c
+      "$_InitializeBuildTool" nuget locals http-cache -c
 
       export NUGET_PLUGIN_HANDSHAKE_TIMEOUT_IN_SECONDS=20
       export NUGET_PLUGIN_REQUEST_TIMEOUT_IN_SECONDS=20

global.json

@@ -7,6 +7,6 @@
     "xcopy-msbuild": "16.3.0-alpha"
   },
   "msbuild-sdks": {
-    "Microsoft.DotNet.Arcade.Sdk": "5.0.0-beta.19480.3"
+    "Microsoft.DotNet.Arcade.Sdk": "5.0.0-beta.19501.4"
   }
 }