Qualcomm AI Engine Direct - refactor unit test (#1475)

Summary:
- refactor testing architecture
- support e2e test
- support regression test for example scripts
- add SM8650 for test coverage

Pull Request resolved: https://github.com/pytorch/executorch/pull/1475

Reviewed By: digantdesai

Differential Revision: D52368657

Pulled By: kimishpatel

fbshipit-source-id: 5cd112b3704f3f787bf9262b1a89115abcb91398