Use NetCorePublic-Pool pool instead of AzDO hosted pool for Browser jobs (#43589)

The hosted pool runs into no disk space issues.

Author: akoeplinger

eng/pipelines/common/xplat-setup.yml

@@ -105,22 +105,19 @@ jobs:
     ${{ if eq(parameters.jobParameters.pool, '') }}:
       pool:
         # Public Linux Build Pool
-        ${{ if and(in(parameters.osGroup, 'Linux', 'FreeBSD'), eq(variables['System.TeamProject'], 'public')) }}:
+        ${{ if and(in(parameters.osGroup, 'Linux', 'FreeBSD', 'Browser'), eq(variables['System.TeamProject'], 'public')) }}:
           name:  NetCorePublic-Pool
           queue: BuildPool.Ubuntu.1604.Amd64.Open
 
         # Official Build Linux Pool
-        ${{ if and(in(parameters.osGroup, 'Linux', 'FreeBSD'), ne(variables['System.TeamProject'], 'public')) }}:
+        ${{ if and(in(parameters.osGroup, 'Linux', 'FreeBSD', 'Browser'), ne(variables['System.TeamProject'], 'public')) }}:
           name: NetCoreInternal-Pool
           queue: BuildPool.Ubuntu.1604.Amd64
 
         # OSX Build Pool (we don't have on-prem OSX BuildPool
         ${{ if in(parameters.osGroup, 'OSX', 'iOS', 'tvOS') }}:
           vmImage: 'macOS-10.15'
 
-        ${{ if eq(parameters.osGroup, 'Browser') }}:
-          vmImage: 'ubuntu-latest'
-
         # Official Build Windows Pool
         ${{ if and(eq(parameters.osGroup, 'Windows_NT'), ne(variables['System.TeamProject'], 'public')) }}:
           name: NetCoreInternal-Pool