Why is shouldRevalidate called 3 times with same parameters?

[sdwxiang]

I noticed that shouldRevalidate is invoked 3 times during a
single navigation, with identical parameters. Looking at the
stack traces, they come from:

1. getMatchesToLoad (navigation phase)
2. runMiddlewarePipeline (middleware phase)
3. callLoaderOrAction (loader phase)

Why not consolidate these checks? Is this intentional design
or could it be optimized?