Remove stress4 and stress5 tests.

- We only request 3 devices and use stress, stress2 and stress3 labels
  only.

BUG=None
TEST=None

Change-Id: I78320da06ab7ca5d7f963a5e9bdf08106617fb81
Reviewed-on: https://chromium-review.googlesource.com/329013
Commit-Ready: danny chan <dchan@chromium.org>
Tested-by: danny chan <dchan@chromium.org>
Reviewed-by: harpreet Grewal <harpreet@chromium.org>
Reviewed-by: Kalin Stoyanov <kalin@chromium.org>
16 files changed