Use for-loop instead of slower any() with generator expression

[jpmckinney]

Drops time spent in type validator from 13% to 7%

Before:

After:

[jpmckinney]

https://github.com/OpenDataServices/cove/pull/609/files#diff-e4978c21ecf1ac03267a96314f0f0e88 added an early return in JsonRefResolver which skipped over add_is_codelist. If I git checkout HEAD~1 from that commit, the code doesn't have the early return. So, I think it was introduced in error.

[Bjwebb]

This is causing the lib-cove-oc4ids tests to fail, and I've not had chance to dig into what's going on, so leaving this unmerged for now.

[jpmckinney]

I think 3a67f14 wasn't working as expected, because it was being called on non-dereferenced schema.

I also reverted the corresponding f91c564 89e8d26 afee2ae

[jpmckinney]

Re-measuring using the commands in open-contracting/lib-cove-oc4ids#23, the time spent in the type validator drops from 10% to 6%.

Before:

After: