Cache and uncache buffers in the same transaction

This removes a race condition where clients may attempt to cache a
buffer before an associated uncache buffer request has completed,
leading to full buffer cache errors in SurfaceFlinger.

GLSurfaceViewTest#testPauseResumeWithoutDelay is failing on barbet and
test logs show frequent `ClientCache::add - cache is full` messages.
This CL fixes the "cache is full" error but does not fix the broken
test.

This reverts commit 1088bbf9.

Reason for revert: b/269141832

Change-Id: I4ba8cf18a367ae6ca94992aabd695d8984fea76f