Fix note checker

[Fumuran]

Our current note checker has a bug: reclaim_height == 0 is considered as if the note could be always reclaimed, while in fact that means that the reclaim is disabled, so the note could never be reclaimed.

We should fix this bug and update our tests to check this scenario.

For more detailed explanation see this discussion.

[bobbinth]

It is not completely clear to me if this is a bug. That is, why treat reclaim_height == 0 as a special case? If the user wants to make the note never reclaimable, then can always just set reclaim_height = u32::MAX_VALUE - or does this cause issue somewhere?

More generally, I'd find it a bit odd that reclaim_height == 0 is "never reclaimable" but reclaim_height == 1 is basically "always reclaimable".