[RenderEngine] Make use of EGL_KHR_surfaceless_context.

Per
https://www.khronos.org/registry/EGL/extensions/KHR/EGL_KHR_surfaceless_context.txt,
when EGL_KHR_surfaceless_context is present, we can make the context current
without specifying draw and read surface, thus we no longer need to create a
1x1 buffer surface.

BUG: 35315015
Test: Build, flash, boot.
Change-Id: Ia5f19cf0f9561bb660708b5a2ae0187593422210