Disable OUTER JOIN(TRUE) -> INNER JOIN rewrite

This rewrite is not valid for OUTER joins as it would give incorrect
results in case when we have empty table on INNER side.
After rewrite query would return no rows, instead
rows from OUTER table complemented with NULLs.

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

@@ -356,7 +356,9 @@ public PlanNode visitJoin(JoinNode node, RewriteContext<Expression> context)
             if (leftSource != node.getLeft() ||
                     rightSource != node.getRight() ||
                     !expressionEquivalence.areExpressionsEquivalent(session, newJoinPredicate, joinPredicate, types)) {
-                if (newJoinPredicate.equals(BooleanLiteral.TRUE_LITERAL)) {
+                if (node.getType() == JoinNode.Type.INNER && newJoinPredicate.equals(BooleanLiteral.TRUE_LITERAL)) {
+                    // this rewrite is not valid for OUTER joins as it would give incorrect results in case when we have empty table on INNER side
+                    // after rewrite query would return no rows, instead rows from OUTER table complemented with NULLs.
                     output = new JoinNode(node.getId(), INNER, leftSource, rightSource, ImmutableList.of(), node.getFilter(), Optional.<Symbol>empty(), Optional.<Symbol>empty());
                 }
                 else {