[Refactor]Deprecate the support for python setup.py test

[HIT-cwh]

Motivation

Refers to open-mmlab/mmcv#1637

Modification

Update the setup.py

BC-breaking (Optional)

Does the modification introduce changes that break the backward compatibility of the downstream repositories?
If so, please describe how it breaks the compatibility and how the downstream projects should modify their code to keep compatibility with this PR.

Use cases (Optional)

If this PR introduces a new feature, it is better to list some use cases here and update the documentation.

Checklist

Before PR:

• Pre-commit or other linting tools are used to fix the potential lint issues.
• Bug fixes are fully covered by unit tests, the case that causes the bug should be added in the unit tests.
• The modification is covered by complete unit tests. If not, please add more unit tests to ensure the correctness.
• The documentation has been modified accordingly, like docstring or example tutorials.

After PR:

• If the modification has potential influence on downstream or other related projects, this PR should be tested with those projects, like MMDet or MMSeg.
• CLA has been signed and all committers have signed the CLA in this PR.

[codecov]

Codecov Report

Merging #60 (85edd5d) into master (64ccbc0) will not change coverage.
The diff coverage is n/a.

❗ Current head 85edd5d differs from pull request most recent head 565a0ae. Consider uploading reports for the commit 565a0ae to get more accurate results

@@           Coverage Diff           @@
##           master      #60   +/-   ##
=======================================
  Coverage   56.58%   56.58%           
=======================================
  Files          83       83           
  Lines        2932     2932           
  Branches      540      540           
=======================================
  Hits         1659     1659           
  Misses       1197     1197           
  Partials       76       76           

Flag	Coverage Δ
unittests	56.58% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 64ccbc0...565a0ae. Read the comment docs.