[BE] Remove manual IP address resolution (#164969)

As https://github.com/pytorch/pytorch/issues/100400 has been closed a while back
Pull Request resolved: https://github.com/pytorch/pytorch/pull/164969
Approved by: https://github.com/seemethere
ghstack dependencies: #164968

.github/actions/setup-linux/action.yml

@@ -86,37 +86,6 @@ runs:
         # Prune all of the docker images
         docker system prune -af
 
-    - name: Manually resolve download.pytorch.org
-      shell: bash
-      continue-on-error: true
-      run: |
-        set +e
-        set -x
-
-        PT_DOMAIN=download.pytorch.org
-        # TODO: Flaky access to download.pytorch.org https://github.com/pytorch/pytorch/issues/100400,
-        # cleaning this up once the issue is fixed. There are more than one resolved IP here, the last
-        # one is returned at random
-        RESOLVED_IP=$(dig -4 +short "${PT_DOMAIN}" | tail -n1)
-
-        if [ -z "${RESOLVED_IP}" ]; then
-          echo "Couldn't resolve ${PT_DOMAIN}, retrying with Google DNS..."
-          RESOLVED_IP=$(dig -4 +short "${PT_DOMAIN}" @8.8.8.8 | tail -n1)
-
-          if [ -z "${RESOLVED_IP}" ]; then
-            echo "Couldn't resolve ${PT_DOMAIN}, exiting..."
-            exit 1
-          fi
-        fi
-
-        if grep -r "${PT_DOMAIN}" /etc/hosts; then
-          # Clean up any old records first
-          sudo sed -i "/${PT_DOMAIN}/d" /etc/hosts
-        fi
-
-        echo "${RESOLVED_IP} ${PT_DOMAIN}" | sudo tee -a /etc/hosts
-        cat /etc/hosts
-
     - name: Check that the docker daemon is running
       shell: bash
       continue-on-error: true