Turn screen off when doing pno stress test

This CL has below changes:
- Turn screen off to trigger pno scans correctly
- Simplify the code flow about pno stress test and wifi selector test

Bug: 120760521
Test: Local
Change-Id: Ice32f2545b2326177e9e19d51c4734152ae860f1
1 file changed
tree: 52865b41417b77e5287bfdf1683f295efeb9329b
  1. acts/
  2. tools/
  3. wts-acts/
  4. Android.mk
  5. PREUPLOAD.cfg