Run build for MUXControlsReleaseTest on WinDevPool-S instead of windows-2019 (#5711)

Author: kmahone

build/AzurePipelinesTemplates/MUX-NugetReleaseTest-Job.yml

@@ -31,8 +31,12 @@ jobs:
     - ${{if parameters.dependsOn }}:
       - ${{ parameters.dependsOn }}
 
-  pool:
-    vmImage: 'windows-2019'
+  pool: 
+    ${{ if eq(variables['System.CollectionUri'], 'https://dev.azure.com/ms/') }}:
+      name: WinDevPoolOSS-S
+    ${{ if ne(variables['System.CollectionUri'], 'https://dev.azure.com/ms/') }}:
+      name: WinDevPool-S
+    demands: ImageOverride -equals WinDevVS16-9
   strategy:
     maxParallel: 10
     matrix: ${{ parameters.matrix }}