[#127] Check the pool_size is nonzero in tensor_avgpool_kernel

[aws-zhehongb]

Issue #, if available:

127

Description of changes:

Check the pool_size is nonzero in tensor_avgpool_kernel

Testing:

• [*] The change is covered by numeric check using nki.baremetal
• The change is covered by performance benchmark test using nki.benchmark
• The change is covered by end-to-end integration test

Pull Request Checklist

• [* ] I have filled in all the required field in the template
• [ *] I have tested locally that all the tests pass
• [ *] By submitting this pull request, I confirm that my contribution is made under the terms of the MIT-0 license.