Camera: Try to remove inflight requests during error notifications

Make it possible for clients to clear the internal inflight queue
as part of error result notifications. For this to work all pending
buffers must be returned previously with the exception of the
result metadata.

Bug: 35652756
Test: Complete Camera/Camera2 CTS without any regressions.
Change-Id: I9d8a6b63364fd254311cda2f8c836b99ee05cacb