message: Fix an assertion that stop crashing tests
  Always set the AffineMap to empty one in case there are empty lower and upper bounds.
diff: @@ -481,19 +481,25 @@ AffineMap ContractionOp::getSourceMap(unsigned i) {
  void ContractionOp::setLowerBounds(ArrayRef<int64_t> bounds) {
  SmallVector<AffineExpr, 6> exprs;
  + AffineMap map = AffineMap::get(getContext());
  + if (bounds.size() != 0) {
  for (auto dim : bounds) {
  exprs.push_back(mlir::getAffineConstantExpr(dim, getContext()));
  }
  - auto map = AffineMap::get(/*dimCount=*/0, /*symbolCount=*/0, exprs);
  + map = AffineMap::get(/*dimCount=*/0, /*symbolCount=*/0, exprs);
  + }
  setAttr(getLowerBoundsAttrName(), AffineMapAttr::get(map));
  }
  void ContractionOp::setUpperBounds(ArrayRef<int64_t> bounds) {
  SmallVector<AffineExpr, 6> exprs;
  + AffineMap map = AffineMap::get(getContext());
  + if (bounds.size() != 0) {
  for (auto dim : bounds) {
  exprs.push_back(mlir::getAffineConstantExpr(dim, getContext()));
  }
  - auto map = AffineMap::get(/*dimCount=*/0, /*symbolCount=*/0, exprs);
  + map = AffineMap::get(/*dimCount=*/0, /*symbolCount=*/0, exprs);
  + }
  setAttr(getUpperBoundsAttrName(), AffineMapAttr::get(map));
  }
  