Flaky test fixes.

cherry pick to tm-qpr-dev due to b/328726214

- don't crash the whole suite in case of test failure,
- wait for 100ms for a second update call.

Bug: 244589479, 328726214
Fixes: 244589479
Test: atest --iterations 100 DeviceConfigTest
Change-Id: Ia985a51d097919bc2885f63d0baf5a77d41ca786
(cherry picked from commit 52fef356)