Revert "Remove tests depending on json-schema"

This reverts commit d2d799314da663e91b1920e32a38d10a2ddb2e76.
(#22360) json-schema needs multi_json 1.7.7
(#22360) don't attempt json schema validation on windows
(#22360) don't include json-schema gem on windows
(maint) accomodate the new location for schemas
Merge pull request #1867 from kylog/issue/22360-reliable-json-schema-validation

(#22360) restore json-schema gem, except on windows