Fixes an issue where we could call evaluate_hardware_support multiple
times each run. Now, instead, we cache the values and use the cache
where needed.
Adds unit test coverage for get_managers and the new method.
Fixes issue where we were caching hardware managers between unit tests.
Closes-bug: 2066308
Change-Id: Iebc5b6d2440bfc9f23daa322493379bbe69e84d0
(cherry picked from commit c39517b044)