Move tests with ids in non-schemas to optional

[jdesrosiers]

Resolves #700

This moves any tests that reference into locations not known to be a schema to the "optional" folder.

[karenetheridge]

I don't understand why this is being done -- are you expecting that implementations could either pass or fail these tests? But some of the things being tested here are mandatory -- such as that keywords that look like identifiers in non-schemas MUST NOT be treated as real identifiers. That's different from simply $ref-ing into non-schemas (which has undefined behaviour in the spec).

[gregsdennis]

@karenetheridge would you then expect only the tests which have pointer $refs that go into non-schema locations be moved to optional? That would leave any tests which use $id-based $refs in required.

[karenetheridge]

Yes, and I thought we'd already done that - because optional/refOfUnknownKeyword.json already exists.

[gregsdennis]

Yeah, I agree with @karenetheridge. These tests definitely are required. I've also left a few comments on them that might not be related to this PR specifically.

(I supposed I should look more closely at the content of the PR than just check to see if my implementation passes.)

[jdesrosiers]

Let's keep discussion in #700. @karenetheridge and @gregsdennis, I'd like to hear what you think about my last comment.

[gregsdennis]

I'm good with these now. Thank you.