Revert "Partial Revert: SurfaceFlinger: Bring back support for mHeap-based screenshots"

This reverts commit 120552e5434979eda6ac45d462f398e9395943aa.
Revert f385f35..3e41bc0

This rolls back to commit f385f356eeb6df4e2fdc89eae003976f346503bb.
Revert "hax: Add back the SURFACE_SKIP_FIRST_DEQUEUE legacy EGL workaround"

This reverts commit f385f356eeb6df4e2fdc89eae003976f346503bb.