Move windows build machines to NetCorePublic-Pool. (#4375)

* Move windows build machines to NetCorePublic-Pool.

* PR feedback.

* PR feedback.

Author: codemzs

.vsts-dotnet-ci.yml

@@ -65,7 +65,8 @@ jobs:
     name: Windows_x64_NetCoreApp21
     buildScript: build.cmd
     pool:
-      name: Hosted VS2017
+      name: NetCorePublic-Pool
+      queue: buildpool.windows.10.amd64.vs2017.open
 
 - template: /build/ci/job-template.yml
   parameters:
@@ -81,12 +82,14 @@ jobs:
         _config_short: RFX
         _includeBenchmarkData: false
     pool:
-      name: Hosted VS2017
+      name: NetCorePublic-Pool
+      queue: buildpool.windows.10.amd64.vs2017.open
 
 - template: /build/ci/job-template.yml
   parameters:
     name: Windows_x86_NetCoreApp21
     architecture: x86
     buildScript: build.cmd
     pool:
-      name: Hosted VS2017
+      name: NetCorePublic-Pool
+      queue: buildpool.windows.10.amd64.vs2017.open