[Refactor] Refactor t-SNE

[fangyixiao18]

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Motivation

Refactor t-SNE to support more backbones, like ViT, Swin, etc.

Modification

Please briefly describe what modification is made in this PR.

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 test 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.

[YuanLiuuuuuu]

We can move all feature analysis tools to MMClassification, and provide an unified entrance later.

[codecov[bot]]

Codecov Report

Base: 81.61% // Head: 81.63% // Increases project coverage by +0.02% :tada:

Coverage data is based on head (548b7ca) compared to base (fbe0ff6). Patch coverage: 100.00% of modified lines in pull request are covered.

:exclamation: Current head 548b7ca differs from pull request most recent head 60584cf. Consider uploading reports for the commit 60584cf to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev-1.x #629 +/- ## =========================================== + Coverage 81.61% 81.63% +0.02% =========================================== Files 135 135 Lines 4961 4961 Branches 672 672 =========================================== + Hits 4049 4050 +1 Misses 774 774 + Partials 138 137 -1 ``` | Flag | Coverage Δ | | |---|---|---| | unittests | `81.63% <100.00%> (+0.02%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-mmlab#carryforward-flags-in-the-pull-request-comment) to find out more. | [Impacted Files](https://codecov.io/gh/open-mmlab/mmselfsup/pull/629?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-mmlab) | Coverage Δ | | |---|---|---| | [mmselfsup/datasets/samplers/deepcluster\_sampler.py](https://codecov.io/gh/open-mmlab/mmselfsup/pull/629/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-mmlab#diff-bW1zZWxmc3VwL2RhdGFzZXRzL3NhbXBsZXJzL2RlZXBjbHVzdGVyX3NhbXBsZXIucHk=) | `95.83% <100.00%> (ø)` | | | [mmselfsup/datasets/transforms/processing.py](https://codecov.io/gh/open-mmlab/mmselfsup/pull/629/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-mmlab#diff-bW1zZWxmc3VwL2RhdGFzZXRzL3RyYW5zZm9ybXMvcHJvY2Vzc2luZy5weQ==) | `89.00% <100.00%> (+0.21%)` | :arrow_up: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-mmlab). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-mmlab)

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