Fix compilation failure caused by -Wall addition.(rapidsai#7134)

rapidsai#7105 somehow got merged but broke compilation. These are the necessary fixes.

Authors:
  - Conor Hoekstra <codereport@outlook.com>

Approvers:
  - Paul Taylor (@trxcllnt)
  - Vukasin Milovanovic (@vuule)

URL: rapidsai#7134

cpp/benchmarks/common/generate_benchmark_input.cpp

@@ -468,8 +468,8 @@ std::unique_ptr<cudf::column> create_random_column<cudf::list_view>(data_profile
   auto list_column = std::move(leaf_column);
   for (int lvl = 0; lvl < dist_params.max_depth; ++lvl) {
     // Generating the next level - offsets point into the current list column
-    auto current_child_column = std::move(list_column);
-    auto const num_rows       = current_child_column->size() / single_level_mean;
+    auto current_child_column      = std::move(list_column);
+    cudf::size_type const num_rows = current_child_column->size() / single_level_mean;
 
     std::vector<int32_t> offsets{0};
     offsets.reserve(num_rows + 1);

cpp/tests/copying/split_tests.cpp

@@ -914,7 +914,7 @@ void split_structs_no_children(SplitFunc Split, CompareFunc Compare)
     std::vector<cudf::size_type> splits{2};
     auto result = Split(*struct_column, splits);
 
-    EXPECT_EQ(result.size(), 2);
+    EXPECT_EQ(result.size(), 2ul);
     Compare(*expected, result[0]);
     Compare(*expected, result[1]);
   }
@@ -933,7 +933,7 @@ void split_structs_no_children(SplitFunc Split, CompareFunc Compare)
     std::vector<cudf::size_type> splits{2};
     auto result = Split(*struct_column, splits);
 
-    EXPECT_EQ(result.size(), 2);
+    EXPECT_EQ(result.size(), 2ul);
     Compare(*expected, result[0]);
     Compare(*expected, result[1]);
   }
@@ -948,7 +948,7 @@ void split_structs_no_children(SplitFunc Split, CompareFunc Compare)
     std::vector<cudf::size_type> splits{4};
     auto result = Split(*struct_column, splits);
 
-    EXPECT_EQ(result.size(), 2);
+    EXPECT_EQ(result.size(), 2ul);
     Compare(*expected0, result[0]);
     Compare(*expected1, result[1]);
   }
@@ -969,7 +969,7 @@ void split_structs_no_children(SplitFunc Split, CompareFunc Compare)
     std::vector<cudf::size_type> splits{4};
     auto result = Split(*struct_column, splits);
 
-    EXPECT_EQ(result.size(), 2);
+    EXPECT_EQ(result.size(), 2ul);
     Compare(*expected0, result[0]);
     Compare(*expected1, result[1]);
   }