MB-67292: Extend test coverage for !fusion

Run most of the unit tests for fusion on a system where fusion
isn't supported (either not supported at all, or not supported
in the provided bucket context) and ensure the commands return
"Not supported" and don't break the system

Change-Id: I4cae95c9ad8ee693001db4a8a98590c0acbc3681
Reviewed-on: https://review.couchbase.org/c/kv_engine/+/229620
Reviewed-by: Paolo Cocchi <[email protected]>
Tested-by: Build Bot <[email protected]>

Author: mohammadzaeem