Benchmarks: Fix Comment - Correct benchmark name in test_gpu_copy_bw_performance.py #263

**Description**
Benchmarks: Fix Comment - Correct benchmark name in test_gpu_copy_bw_performance.py.

tests/benchmarks/micro_benchmarks/test_gpu_copy_bw_performance.py

 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT License.
 
-"""Tests for disk-performance benchmark."""
+"""Tests for gpu-copy-bw benchmark."""
 
 from pathlib import Path
 import numbers