search-blitz: extra queries for dogfood
Created by: keegancsmith
We want to run search blitz on dogfood. However, we need extra queries to target gigarepo which is only available on dogfood. This commit adds logic to take the existing queries and add extra queries based on the environment variable SEARCH_BLITZ_ENV.
Test Plan: CI and manual testing on dogfood.
This is an alternative implementation to https://github.com/sourcegraph/sourcegraph/pull/33436