fix: Fix a null bit set in left index lookup join (facebookincubator#…

…12226)

Summary:
Pull Request resolved: facebookincubator#12226

Fix null bit setting in left index lookup join as the bits fill take [start, end) but not {start, length}.
Found in Meta internal tests.

Reviewed By: zacw7

Differential Revision: D68941198

fbshipit-source-id: 5f124394f6c3b0a9e370ca413ebdc58a509d67c3

velox/exec/IndexLookupJoin.cpp

@@ -453,7 +453,7 @@ RowVectorPtr IndexLookupJoin::produceOutputForLeftJoin() {
       bits::fillBits(
           rawLookupOutputNulls_,
           numOutputRows,
-          numOutputMissedInputRows,
+          numOutputRows + numOutputMissedInputRows,
           bits::kNull);
       for (auto i = 0; i < numOutputMissedInputRows; ++i) {
         rawProbeOutputRowIndices_[numOutputRows++] = ++lastProcessedInputRow;