Wrong result from internal merged([{'multipleOf': 2}, {'not': {'maximum': 0}}])

[Zac-HD]

I think this is something to do with the intermediate inference of the types as integer and number respectively, and the way those types actually overlap. Could be located in canonicalisation or merging, really.

As well as adding an explicit regression test we'll want to re-enable the "draft7/validate against correct branch, then vs else" entry in our test corpus.