enable ndarray.mean tests on GPU

Author: Alexander-Makaryev

tests/skipped_tests_gpu.tbl

@@ -1549,8 +1549,6 @@ tests/third_party/cupy/statistics_tests/test_histogram.py::TestHistogram::test_h
 tests/third_party/cupy/statistics_tests/test_histogram.py::TestHistogram::test_histogram_same_value
 tests/third_party/cupy/statistics_tests/test_histogram.py::TestHistogram::test_histogram_weights_basic
 tests/third_party/cupy/statistics_tests/test_histogram.py::TestHistogram::test_histogram_weights_mismatch
-tests/third_party/cupy/statistics_tests/test_meanvar.py::TestMeanVar::test_mean_all
-tests/third_party/cupy/statistics_tests/test_meanvar.py::TestMeanVar::test_mean_axis
 tests/third_party/cupy/statistics_tests/test_meanvar.py::TestNanMeanAdditional::test_nanmean_all_nan
 tests/third_party/cupy/statistics_tests/test_meanvar.py::TestNanMeanAdditional::test_nanmean_float16
 tests/third_party/cupy/statistics_tests/test_meanvar.py::TestNanMeanAdditional::test_nanmean_huge