Save an early test summary in case the test launcher crashes or gets killed

This may turn some infra failures (purple) into INVALID_TEST_RESULTS (red)
in case the test launcher is for example early terminated on swarming.

See bug for more details.

BUG=649831

Review-Url: https://codereview.chromium.org/2411003003
Cr-Commit-Position: refs/heads/master@{#424709}


CrOS-Libchrome-Original-Commit: 5dc1ee3fccf13062e1ee9b1fbb25189f617c74c8
4 files changed
tree: 87efc846d2e02778c61b9d5c51075bf389f5d36a
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/