[TEST] Update timeout-related tests to use TIMEOUT #define

[levincent06]

In message.h, we define TIMEOUT to be the maximum number of milliseconds to wait between each message from a device.

We have some tests that connect virtual faulty devices (ForeignTestDevice and UnstableTestDevice). If the test relies on waiting for these devices to timeout, the sleep() duration should be some multiple of TIMEOUT instead of a hardcoded value (ex: 5 seconds)