Advance client to match server position when preparing buffer for starting.

When stopping a stream, there can be stale data that hasn't been played.
The framework will erase the data memory to avoid playing stale data.
After erasing the data, advance client to match server position so that
the service side don't need to read stale data and cause the shared
mixer to run before the client writing data.

Bug: 391650832
Test: atest AAudioTests
Flag: EXEMPT bugfix
Change-Id: Ia46d3773c49b7b29f7ce23eda71692d193688bdd