aebc829c4e
This adds a tools/ script that checks any cherry-picked hashes on the current commit (or a provided commit) to make sure that all the hashes exist on at least master or stable/.* branches. This should help avoid accidentally merging stable backports where one of the hashes along the line has changed due to conflicts. Change-Id: I4afaa0808b75cc31a8dd14663912c162281a1a42