[Java] Code cleanup for dictionary encoding #22394
Description
In last few weeks, we did some refactor in dictionary encoding.
Since the new designed hash table for DictionaryEncoder and hashCode & equals API in ValueVector already checked in, some classed are no use anymore like DictionaryEncodingHashTable, BaseBinaryVector and related benchmarks & UT.
Fortunately, these changes are not made into version 0.14, which makes possible to remove them.
Reporter: Ji Liu / @tianchen92
Assignee: Ji Liu / @tianchen92
PRs and other links:
Note: This issue was originally created as ARROW-5986. Please see the migration documentation for further details.