Update RLS to disable spurious client_find_definitions test

Since switching CI to Azure Pipelines it seems that this test seems
to fail more consistently, so let's disable that for now. It helps
that we have less than a week before release - we disallow PRs that
break the tools to land in this period, so this makes landing critical
PRs smoother  now.

r? @alexcrichton

Author: Xanewok