A long-standing problem has been that I couldn't spread code across
'run' blocks because they were separate scopes, so I've ended up making
them effectively comments. Running code inside a 'run' block is
identical in every way to simply running the code directly. The 'run'
block is merely a visual aid to separate setup from the component under
test.
In the process I've also standardized all Mu scenarios to always run in
a local scope, and only use (raw) numeric addresses for values they want
to check later.