cras_api_test: Stress test for input stream.

The stress test could be used to re-produce a bug that cras cannot read
from input device.

BUG=b:29142540
TEST=Run 'cras_api_test -n 100' on cyan.

Change-Id: I396a866f851ec5e666d3fe0f7d5b1436daa9f459
Reviewed-on: https://chromium-review.googlesource.com/358750
Commit-Ready: Chinyue Chen <chinyue@chromium.org>
Tested-by: Chinyue Chen <chinyue@chromium.org>
Reviewed-by: Cheng-Yi Chiang <cychiang@chromium.org>
2 files changed