compact spatial IR through different new operations and dedicated syntax

fast spatial node merging with batch operations

src/PIM/Conversion/ONNXToSpatial/Patterns/Math/MatMul.cpp

@@ -232,9 +232,7 @@ struct MatMulToGemm : OpRewritePattern<ONNXMatMulOp> {
       }));
     }
 
-    Value result = batchResults.size() == 1
-                   ? batchResults.front()
-                   : tensor::ConcatOp::create(rewriter, loc, /*axis=*/0, batchResults).getResult();
+    Value result = createSpatConcat(rewriter, loc, /*axis=*/0, batchResults);
     rewriter.replaceOp(matmulOp, result);
     return success();
   }