SERVER-36718 and SERVER-37074 (re-)introduced code to ensure that the validate cmd in the ValidateCollections test hook would only run against FCV 4.2 in v4.2 and that we finished downgrading to FCV 4.0 if necessary before upgrading to FCV 4.2. This was due to an index format change that occurred in FCV 4.2 and then continued to exist after downgrade to FCV 4.0, which validate did not allow in FCV 4.0.

We do not need FCV handling in the validate test hook in v4.4; and we should not be only running the validate cmd against FCV 4.2 in v4.4.