[Ubuntu] add runner-package to curated images (#8474)

images/linux/scripts/installers/runner-package.sh

@@ -0,0 +1,18 @@
+#!/bin/bash -e
+################################################################################
+##  File:  runner-package.sh
+##  Desc:  Downloads and Installs runner package
+################################################################################
+
+# Source the helpers for use with the script
+source $HELPER_SCRIPTS/install.sh
+
+DOWNLOAD_URL=$(get_github_package_download_url "actions/runner" 'test("actions-runner-linux-x64-[0-9]+\\.[0-9]{3}\\.[0-9]+\\.tar\\.gz")')
+
+FILE_NAME="${DOWNLOAD_URL##*/}"
+
+sudo mkdir -p /opt/runner-cache
+
+download_with_retries "${DOWNLOAD_URL}" "/tmp" "${FILE_NAME}"
+
+sudo mv /tmp/$FILE_NAME /opt/runner-cache/$FILE_NAME

images/linux/scripts/tests/RunnerCache.Tests.ps1

@@ -0,0 +1,7 @@
+Describe "RunnerCache" {
+    Context "runner cache directory not empty" {
+        It "/opt/runner-cache not empty" {
+            (Get-ChildItem -Path "/opt/runner-cache/*.tar.gz" -Recurse).Count | Should -BeGreaterThan 0
+        }
+    }
+}