Merge "swapchain: increase the minimal buffer count to 3" into sc-dev am: e74b34d0 am: 82e1fb10 am: 4043e1b8

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/native/+/15030431

Change-Id: Ifafcc8521427fd0a963e79006673111a17d603f6