Don't update BufferQueue FrameEventStats when a frame is dropped

Update BlastBufferQueue to match BQ logic. This change in behaviour
was causing a dEQP test failure which relied on actual present timestamps
to generate future desired present timestamps. If a buffer was dropped,
the actual present timestamp retrieved would be 0 causing cascading failures.

Test: atest BLASTFrameEventHistoryTest
Test: CtsDeqpTestCases:dEQP-VK.wsi.android.display_timing.fifo#display_timing
Bug: 186200443
Change-Id: I9589d6e43c5f6dfbe93702b7c43a8fff8712fe24