WT-3955 added verbose messages for non-WiredTiger errors. This ticket is to extend that work for WiredTiger errors.

I expect we want to add verbose messages for WT_ROLLBACK, WT_ERROR, WT_PANIC and WT_RUN_RECOVERY, but not for WT_DUPLICATE_KEY, WT_NOTFOUND, WT_RESTART, WT_CACHE_FULL and WT_PREPARE_CONFLICT.