Clear timeouts between tests.

This is to avoid overloading the background handler with timeouts when
running our CTS tests.
This will also prevent potential racyness in tests whereby a timeout
ends up leaking to another test.

Bug: 221401739
Test: atest CtsSafetyCenterTestCases
Change-Id: I83b09d9c7619034b5c075fe1e1016f195f0cd453
1 file changed