### What changes were proposed in this pull request?
Currently, when a client requests FETCH_PRIOR to Thriftserver, Thriftserver reiterates from the start position. Because Thriftserver caches a query result with an array when THRIFTSERVER_INCREMENTAL_COLLECT feature is off, FETCH_PRIOR can be implemented without reiterating the result. A trait FeatureIterator is added in order to separate the implementation for iterator and an array. Also, FeatureIterator supports moves cursor with absolute position, which will be useful for the implementation of FETCH_RELATIVE, FETCH_ABSOLUTE.
### Why are the changes needed?
For better performance of Thriftserver.
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
FetchIteratorSuite
Closes#30600 from Dooyoung-Hwang/refactor_with_fetch_iterator.
Authored-by: Dooyoung Hwang <dooyoung.hwang@sk.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
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