Update TestSpacing and TestTensordot

[vlad-perevezentsev]

This PR suggests using assert_allclose instead of assert_equal with a resolution-based tolerance in TestSpacing::test_zeros to fix test failures on CUDA caused by excessive precision for float32.

Mismatched elements: 2 / 2 (100%)
E           Max absolute difference among violations: 1.1754942e-38
E           Max relative difference among violations: 8388607.
E            ACTUAL: array([ 1.175494e-38, -1.175494e-38], dtype=float32)
E            DESIRED: array([ 1.e-45, -1.e-45], dtype=float32)

$ ONEAPI_DEVICE_SELECTOR=cuda pytest dpnp/tests/test_mathematical.py::TestSpacing::test_zeros
==============================2 passed in 1.18s =================================

And updates TestTensordot::test_axes and TestTensordot::test_linalg to increase a factor parameter in assert_dtype_allclose for scaling tolerance

E           Mismatched elements: 1 / 144 (0.694%)
E           Max absolute difference among violations: 1.28230759e-14
E           Max relative difference among violations: 2.90345891e-14
E            ACTUAL: array([[[[ 7.000190e+01,  1.559230e+01, -6.848580e+01],
E                    [ 5.029798e+01,  2.133680e+02, -5.294881e+01],
E                    [-6.261007e+01, -5.260484e+00,  9.316735e+00],...
E            DESIRED: array([[[[ 7.000190e+01,  1.559230e+01, -6.848580e+01],
E                    [ 5.029798e+01,  2.133680e+02, -5.294881e+01],
E                    [-6.261007e+01, -5.260484e+00,  9.316735e+00],...

FAILED dpnp/tests/test_product.py::TestTensordot::test_axes[axes1-float64] - AssertionError:
FAILED dpnp/tests/test_product.py::TestTensordot::test_axes[axes1-None] - AssertionError:
FAILED dpnp/tests/test_product.py::TestTensordot::test_linalg[axes1] - AssertionError:

• Have you provided a meaningful PR description?
• Have you added a test, reproducer or referred to issue with a reproducer?
• Have you tested your changes locally for CPU and GPU devices?
• Have you made sure that new changes do not introduce compiler warnings?
• Have you checked performance impact of proposed changes?
• If this PR is a work in progress, are you filing the PR as a draft?

[github-actions]

View rendered docs @ https://intelpython.github.io/dpnp/pull/2251/index.html

[coveralls]

coverage: 65.08%. remained the same
when pulling fac6342 on update_test_spacing_cuda
into 1bed3bd on master.