ci speed work 1 (#10676)

* skip a few slow tests

* use a venv for python packages

* create venv

* no user, it's in venv

* ignore venv

* venv

* new cache key

* try that

* this

* version the python cache

.github/workflows/test.yml

@@ -1,7 +1,8 @@
 name: Unit Tests
 env:
   # increment this when downloads substantially change to avoid the internet
-  DOWNLOAD_CACHE_VERSION: '9'
+  DOWNLOAD_CACHE_VERSION: '10'
+  PYTHON_CACHE_VERSION: '1'
   CAPTURE_PROCESS_REPLAY: 1
   GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}