support long and infinite timeouts in WaitForOrchestrationAsync

[sebastianburckhardt]

Currently, long or infinite timeout arguments to IOrchestrationServiceClient.WaitForOrchestrationAsync are not correctly handled:

1. infinite timeouts (-1 milliseconds) are ignored and instead time out immediately
2. long timeouts can lead to state pollution because they are persisted in the partition state until the timeout expires, even if the client is long gone.

To fix this, this PR adds some code to break long or infinite timeouts into 5-minute portions. It runs these portions in a loop until the timeout expires or the wait completes with a result.