Add unittesting for the bufferQueueConsumer::acquireBuffer

The bufferQueueConsumer::acquireBuffer code is tricky and hard to maintain. We will need to make changes to this code to implement the new vulkan timings extension. Add unit tests to verify the existing behaviour and prevent breakages.

Test: unit tests added
Flag: Flag: EXEMPT unit tests
Bug: 378669647
Change-Id: I00f3f92a03b861f64b394cbc1c1e6eab64000246