Avoid caching front-buffered layers

If the buffer has FRONT_BUFFER we need to tell planner
that the buffer changed even though the buffer pointer/id
didn't.

Bug: 217776226
Test: LayerStateTest::updateBufferSingleBufferedUsage
Change-Id: Ia0f603a1dfea652c7393948ee9ef54e0f998ab88
2 files changed