[FEA] Reusable filtered joins in Java for semi/anti joins

**Is your feature request related to a problem? Please describe.**

cudf-spark would like to be able to cache and reuse broadcast hash builds across stream batches. Currently the Java APIs for left semi/anti joins construct a filtered join for each call.

**Describe the solution you'd like**

We can wrap the `libcudf::filtered_join` in Java/JNI, and add `Table.leftSemiJoinGatherMap` and `Table.leftAntiJoinGatherMap` APIs that accept the reusable `FilteredJoin` object. This would closely follow what has been done for HashJoin and DistinctHashJoin.

This request just concerns equi-joins, additional residual predicates would be out of scope.

**Describe alternatives you've considered**

Reusable semi/anti joins can be emulated with a reusable HashJoin to perform an inner join, and turning the result into a semi/anti gather maps, at the cost of enormous intermediate gather maps if there are many duplicates.

**Additional context**

Start by locating the existing Java/JNI bindings for libcudf::filtered_join and the HashJoin and DistinctHashJoin implementations. Trace how Table.leftSemiJoinGatherMap and Table.leftAntiJoinGatherMap currently construct filtered joins, then define the reusable FilteredJoin path. Done means reusable equi-join gather-map APIs are exposed for both semi and anti joins, with residual predicates remaining out of scope.

Written by the indexing model from the issue text.