Fork RenderEngine

RenderEngine is going to undergo some evolution and
is at this point not interested in clients other
than SurfaceFlinger. Land a copy into stagefright so
it can continue with whatever it was doing.

As renderengine was a static library, this should have
no change on binary sizes.

Test: builds; no behavior changes otherwise
Bug: 167727943
Change-Id: Id69680e0c9558dac672f2fabbf4d2c268a8d0e64