Enable/disable optimize for android_test and android_test_helper_app by default.

Follow up to https://android-review.git.corp.google.com/c/platform/build/bazel/+/2727853/comment/f2c5802e_245fd302/

Test: New unit tests, presubmits
Test: `atest-dev HelloWorldTests --roboleaf-mode=dev`

Change-Id: I88efcf72fbcb717d05e71ba50ba7802c3bece816