Add python3 support to case test_ipinip_hash and test_ipinip_hash_negative of fib test

[echuawu]

Description of PR

Add python 3 support to fib test

Including 2 cases test_ipinip_hash and test_ipinip_hash_negative

Summary: Fixes # (issue)

Type of change

• [ ] Bug fix
• [ ] Testbed and Framework(new/improvement)
• [x] Test case(new/improvement)

Back port request

• [ ] 201911
• [ ] 202012
• [x] 202205
• [x] 202305
• [x] 202311

Approach

What is the motivation for this PR?

It was found that the 2 cases are still using python 2 when running PTF test

How did you do it?

Add python 3 support

How did you verify/test it?

Validate it by local run

Any platform specific information?

Supported testbed topology if it's a new test case?

Documentation

[liat-grozovik]

@nhe-NV @roy-sror could you please review?

[liat-grozovik]

@wangxin kindly help to review or suggest someone to do so

[bingwang-ms]

The test_ipinip_hash was skipped on Mellanox platform because of a known limitation. https://github.com/sonic-net/sonic-mgmt/pull/8398 Is the issue resolved?

[echuawu]

The test_ipinip_hash was skipped on Mellanox platform because of a known limitation. #8398 Is the issue resolved?

It has not been fixed. And it's not conflict with this PR, it just update the test script.