Migrate tools CI to GA

clean-toolcache.ps1

@@ -3,6 +3,11 @@ param (
 )
 
 $targetPath = $env:AGENT_TOOLSDIRECTORY
+if ([string]::IsNullOrEmpty($targetPath)) {
+    # GitHub Windows images don't have `AGENT_TOOLSDIRECTORY` variable
+    $targetPath = $env:RUNNER_TOOL_CACHE
+}
+
 if ($ToolName) {
     $targetPath = Join-Path $targetPath $ToolName
 }