Fix printing wrong message on remote resolution

[mstoykov]

Previously we will always print the really long message that says we
tried everything. But in reality we only do this if we have something
that:

• is not local (start with ./)
• is not prefixed with https://
• is not a magical github or cdnjs URL (which entirely uses the Opaque
  URL property)

But the if changed here basically checks that either we don't have
scheme or that it's Opaque. But in reality if it has scheme it never
has Opaque. And Opaque always has no scheme - so all cases enter the if.

The correct is to enter only when both are true as in that case it's
not magical and it doesn't have scheme so the schem

[codebien]

And Opaque always has no scheme - so all cases enter the if.

@mstoykov Apparently, the old error message mentions the nodejs case, where for example seems node:fs would be resolved with a scheme and opaque.

Example url resolution with Go:

u, err := url.Parse("node:fs")
fmt.Println(u.Scheme) // node
fmt.Println(u.Opaque) // fs

Is the logic before the if changing it making the scheme empty?

It seems the case is not covered by the tests, can we add it? It should help with "documenting" the case.

[mstoykov]

The message predates nodejs introducing the node scheme and is still printed in those cases ;) This actually exists for everybody who just wrote require("fs") or something similar

We don't really support anything but https and file as a scheme either way. But in this particular case it just sidestep this and gets in a totally different part of the code returning the same error.

Given that this still works I really don't want to touch this more as this code is convoluted enough. And until we decide to deprecate at least the https:// prefixing of everything it will continue to be so. If we decide to completely drop it (and especially if we also drop the special "magical" urls) I guess we will be able to in practice delete 80+% of the code that deals with those.

Even this fix in practice just makes a fairly rare case a bit less confusing, but if it required any more than this change I would probably just drop it.