[BUG] Disable flaky cpp test AnnIVFFlatTestF_half.AnnIVFFlat/21 (#1092)

Disable flaky `AnnIVFFlat` test. See #1091 for more details.

Authors:
  - Julian Miller (https://github.com/julianmi)

Approvers:
  - Tamas Bela Feher (https://github.com/tfeher)

URL: #1092

Author: julianmi

cpp/tests/neighbors/ann_ivf_flat.cuh

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024, NVIDIA CORPORATION.
+ * Copyright (c) 2024-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -561,7 +561,9 @@ const std::vector<AnnIvfFlatInputs<int64_t>> inputs = {
   {1000, 10000, 2049, 16, 40, 1024, cuvs::distance::DistanceType::CosineExpanded, false},
   {1000, 10000, 2050, 16, 40, 1024, cuvs::distance::DistanceType::InnerProduct, false},
   {1000, 10000, 2050, 16, 40, 1024, cuvs::distance::DistanceType::CosineExpanded, false},
-  {1000, 10000, 2051, 16, 40, 1024, cuvs::distance::DistanceType::InnerProduct, true},
+  // TODO: Re-enable test after adjusting parameters for higher recall. See
+  // https://github.com/rapidsai/cuvs/issues/1091
+  // {1000, 10000, 2051, 16, 40, 1024, cuvs::distance::DistanceType::InnerProduct, true},
   {1000, 10000, 2051, 16, 40, 1024, cuvs::distance::DistanceType::CosineExpanded, true},
   {1000, 10000, 2052, 16, 40, 1024, cuvs::distance::DistanceType::InnerProduct, false},
   {1000, 10000, 2052, 16, 40, 1024, cuvs::distance::DistanceType::CosineExpanded, false},