Change integrations/tensorflow/e2e tests to use iree_py_test.
Change integrations/tensorflow/e2e tests to use iree_py_test.

Fixes OSS failures to import modules following https://github.com/google/iree/pull/682.

Closes https://github.com/google/iree/pull/690

COPYBARA_INTEGRATE_REVIEW=https://github.com/google/iree/pull/690 from ScottTodd:python-tf 32825670e2b948721d726b73201eb98c1c3571c3
PiperOrigin-RevId: 293624433

iree-org/iree,iree-org/iree,iree-org/iree,iree-org/iree,google/iree,google/iree,google/iree,iree-org/iree,google/iree,google/iree,iree-org/iree,google/iree,google/iree,iree-org/iree