Migrate to 1ES hosted pools (#1679)

.vsts-ci.yml

@@ -58,8 +58,8 @@ stages:
           ${{ if or(eq(variables['System.TeamProject'], 'public'), in(variables['Build.Reason'], 'PullRequest')) }}:
             name: Hosted VS2017
           ${{ if and(ne(variables['System.TeamProject'], 'public'), notin(variables['Build.Reason'], 'PullRequest')) }}:
-            name: NetCoreInternal-Pool
-            queue: buildpool.windows.10.amd64.vs2017
+            name: NetCore1ESPool-Internal
+            demands: ImageOverride -equals build.windows.10.amd64.vs2017
         variables:
         - HelixApiAccessToken: ''
         - _InternalBuildArgs: ''