ESQL: push more filters to the right of a JOIN #134153
Description
Description
This is to investigate if we can push more aggressively on the RHS of a join: #133166 pushes to the RHS the filters applied after the join, but only if these aren't on the join field(s) (since these are currently considered LHS filters only).
However, generally, the ones on the join fields could be pushed on the RHS too, to avoid loading and joining the values that would then be discarded by the filter left on top of the join.
This wouldn't be necessary for all joins (like LOOKUP JOIN, where we build term queries on the lookup index, which are restrictive enough already), but could benefit other hash type of joins.