Remove timeout from waitForBroadcastIdle to improve spikiness.

A timeout was added to BenchmarkRunner.waitForBroadcastIdle method in
ag/27491356 I91579d8af35b4a7df76d6bc1bcfad328c107d7c2
and this caused the UserLifecycleTests results to be more spiky.
This CL reverts that change, and also increases the timeout in
waitForCpuIdle.

Bug: 342399089
Bug: 340812874
Test: atest UserLifecycleTests
Flag: None
Change-Id: I2686625530fc64552d4380ad63fd5235d3364f5e