Fix flaky vibration thread tests

Remove tests that rely on sleep in favor for waiting on contidions
expected for the thread to reach during the test. The condition check is
timed out, so the test should fail if they are never met.

Fix: 178080797
Test: VibrationThreadTest
Change-Id: Ie1f912c164f8ccbbcdf79881d3865d89c7cc60c4