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.

Bug: 264892858
Test: presubmits
Test: GLSurfaceViewTest#testPauseResumeWithoutDelay on barbet
Change-Id: I9a075054d11c819307cd837fcfbdc03d8faf5086