mugen test framework

[YaoZengzeng]

Please provide an in-depth description of the question you have:

I found that there is a test framework called mugen in Kmesh source code.

But it seems like it hasn't been updated for a long time.

What do you think about this question?:

It also looks like an integration test. How is it different from the e2e test we are about to merge?

If it can cover scenarios that e2e cannot cover, can it be added to CI?

If it is no longer used, can it be deleted from the source code?

Environment:

• Kmesh version: N/A
• Others: N/A

[YaoZengzeng]

Will delete related code after E2E can cover all the scenarios of mugen, keep it now.