BF-42904 was raised due to an invariant in `addDropPendingIdent()` expecting that the ident is not already being tracked as drop-pending.  This only occured once in jsfuzztests on the index-build abort path on the constraint-violations ident. Since it hasn't been able to be reproduced, we need to add some additional logging to `addDropPendingIdent()` concerning "internal-constraintViolations-"so that the next time this happens we will capture more information.