Regarding the flag, WT_CURSTD_IGNORE_TOMBSTONE:
What this flag means is that, if set, the caller is okay if the underlying cursor returns a value with a globally visible tombstone. This is only used with the history store cursor implementation.

The meaning implied by the flag naming is that the cursor will ignore the tombstone, whereas it really means is that it is OK to return tombstones.

We should clean this up by finding a more intuitive name for the flag.

This came out of a discussion on the review of the pull request for WT-7757.