OOMCTC: Items in multiple regions may get pruned in intersection operation

[dbahrdt]

The old code already has this right. But the "newer" variant with out-of-memory creation still does not contain "fixes" to this problem.
Unfortunately it seems that this query might actually exist in the wild.
Hence we need to support it.

Copied from TextSearchTraits.h:
If an item spans multiple regions then the item also has to be added to the respective region search strings.
Consider the query (highway fellbach) / (highway stuttgart) which should result in all highways that are in stuttgart and fellbach.
In order for this to work correctly fellbach/stuttgart needs to deref into the enclosed full-match cells AND partial-match cells containing the items that are part of fellbach/stuttgart AND part of something else

[dbahrdt]

Implemented. Unfortunately implementing this by adding partial-match cells to region strings is not enough to support the region query. Additionally this will result in these items to be returned in item queries even though only the region has a matching string. In order to fix this we have to split the data as is the case already in the osi-compare repo.