Always output left side join key for inner join

Author: feilong-liu

presto-main-base/src/main/java/com/facebook/presto/sql/planner/optimizations/UnaliasSymbolReferences.java

@@ -591,7 +591,7 @@ public PlanNode visitJoin(JoinNode node, RewriteContext<Void> context)
             if (node.getType().equals(INNER)) {
                 canonicalCriteria.stream()
                         .filter(clause -> clause.getLeft().getType().equals(clause.getRight().getType()) && clause.getLeft().getType().equalValuesAreIdentical())
-                        .filter(clause -> node.getOutputVariables().contains(clause.getLeft()))
+                        .filter(clause -> node.getOutputVariables().contains(clause.getRight()))
                         .forEach(clause -> map(clause.getRight(), clause.getLeft()));
             }