Do not report Deqp results as failures if device is disconnected.

- When encountering unrecoverable DNRE, do not mark tests in current
  working set as failures. This was done to prevent external recovery
  (re-exec until all done) from causing a non-terminating loop if one
  of test reliably killed the device. With improved scheduling and
  recovery, this is no longer necessary.
- Improve test instance scheduler. Maintain a record of unstable
  (process-killing, device-killing, not executable) tests and avoid
  scheduling unstable and stable tests in the same batch. Run
  potentially unstable tests with smaller batch sizes. This also
  fixes bug 19440384.
- Add tests for non-executable tests.

Change-Id: Ie53b977e7806bd4f74207ce2cc44e82083d1ad07
2 files changed