opt: fix execbuilder output column count for lookup joins

This commit fixes a bug in the execbuilder, which was determining
the number of output columns incorrectly for lookup joins. In particular,
if the join was a semi- or anti-join, the execbuilder was incorrectly
including the right side columns in the column count. This commit
fixes the code so it only includes left side columns for semi- and
anti-joins.

This commit also fixes a bug in the DistSQL planner that was masked
by the bug in the execbuilder. In particular, the output types slice
for lookup semi- and anti-joins incorrectly included the types from the
right side columns. This commit fixes it to only include types for the
left side columns.

Fixes #40562

Release note (bug fix): Fixed an error that could occur when the
optimizer created a plan with a lookup semi- or anti-join nested
inside of another join.

pkg/sql/distsql_physical_planner.go

@@ -1989,6 +1989,7 @@ func (dsp *DistSQLPlanner) createPlanForLookupJoin(
 		// For anti/semi join, we only produce the input columns.
 		planToStreamColMap = planToStreamColMap[:numInputNodeCols]
 		post.OutputColumns = post.OutputColumns[:numInputNodeCols]
+		types = types[:numInputNodeCols]
 	}
 
 	// Instantiate one join reader for every stream.

pkg/sql/opt/exec/execbuilder/relational.go

@@ -1238,6 +1238,10 @@ func (b *Builder) buildLookupJoin(join *memo.LookupJoinExpr) (execPlan, error) {
 	allCols := joinOutputMap(input.outputCols, lookupColMap)
 
 	res := execPlan{outputCols: allCols}
+	if join.JoinType == opt.SemiJoinOp || join.JoinType == opt.AntiJoinOp {
+		// For semi and anti join, only the left columns are output.
+		res.outputCols = input.outputCols
+	}
 
 	ctx := buildScalarCtx{
 		ivh:     tree.MakeIndexedVarHelper(nil /* container */, allCols.Len()),