ISPN-13968 Use next inner node if cache segment not found in leaf when using SIFS

[jabolina]

https://issues.redhat.com/browse/ISPN-13968

Not actually a problem with the rolling upgrade, but an edge case in SIFS. In a store with multiple segments, a segment can have multiple inner nodes, and recursively, we try to find a cache segment within the node.

The problem happens when a cache segment maps to the next node. Currently, we return and set the keys as not found. I've added a change: if the starting leaf we have is not holding data about the cache segment we want, we then try only the next one; if the next does not have the cache segment, we return.

Using the reproducer Gustavo wrote, we have:

CHECKING MIGRATED DATA
TOTAL IS: 5000
REQUEST IS: 5000
eviction cache - TEST PASSED
5000 entries

[wburns]

I have to look closer at the changes, however I would suggest changing the JIRA name to be more descriptive of what actually the issue is.

[wburns]

Changes look good 👍 Just would like to add some more clarification what is going on.

[jabolina]

@tristantarrant should we backport?

[wburns]

Integrated into main, thanks @jabolina !