Use a new cache in build.yml workflow.

[revit13]

This PR does the following to better use action/cache in build.yaml workflow:

• it uses a new cache. the old one seems to contain small part of the tools such that most of the tools were created in each job in make install-tools step, so the key is changed, and thus a new cache is created and used. (an alternative was to delete the old cache with rest api calls)
• it deletes the usage of restore-keys
• it adds ${{ github.workspace }}/hack/tools/lib to the path in the cache. this dir is used by or-tools
• it uses pierotofy/set-swap-space@master action for jobs that run the optimizer to increase memory.