Fix malloc/delete[] mismatch

It's not correct to use delete[] to free a malloc allocation.
This commit changes those allocations to use std::make_unique<int[]>,
so we no longer need manual deallocation.

Fixes #807.

cpp/test/sparse/sort.cu

@@ -22,6 +22,7 @@
 #include <raft/sparse/op/sort.cuh>
 
 #include <iostream>
+#include <memory>
 
 namespace raft {
 namespace sparse {
@@ -60,30 +61,26 @@ TEST_P(COOSort, Result)
 
   uniform(h, r, in_vals.data(), params.nnz, float(-1.0), float(1.0));
 
-  int* in_rows_h = (int*)malloc(params.nnz * sizeof(int));
-  int* in_cols_h = (int*)malloc(params.nnz * sizeof(int));
-  int* verify_h  = (int*)malloc(params.nnz * sizeof(int));
+  auto in_rows_h = std::make_unique<int[]>(params.nnz);
+  auto in_cols_h = std::make_unique<int[]>(params.nnz);
+  auto verify_h  = std::make_unique<int[]>(params.nnz);
 
   for (int i = 0; i < params.nnz; i++) {
     in_rows_h[i] = params.nnz - i - 1;
     verify_h[i]  = i;
     in_cols_h[i] = i;
   }
 
-  raft::update_device(in_rows.data(), in_rows_h, params.nnz, stream);
+  raft::update_device(in_rows.data(), in_rows_h.get(), params.nnz, stream);
 
-  raft::update_device(in_cols.data(), in_cols_h, params.nnz, stream);
-  raft::update_device(verify.data(), verify_h, params.nnz, stream);
+  raft::update_device(in_cols.data(), in_cols_h.get(), params.nnz, stream);
+  raft::update_device(verify.data(), verify_h.get(), params.nnz, stream);
 
   op::coo_sort(
     params.m, params.n, params.nnz, in_rows.data(), in_cols.data(), in_vals.data(), stream);
 
   ASSERT_TRUE(raft::devArrMatch<int>(
     verify.data(), in_rows.data(), params.nnz, raft::Compare<int>(), stream));
-
-  delete[] in_rows_h;
-  delete[] in_cols_h;
-  delete[] verify_h;
 }
 
 INSTANTIATE_TEST_CASE_P(SparseSortTest, COOSort, ::testing::ValuesIn(inputsf));