Revert "remove support for glReadPixels screenshot path"

This reverts commit 3ca76f416bc8665a97636ca8a2d0128b9da9d92c.

Change-Id: I3a91c39a8cac64363afc58554d47b62b0510360d
SurfaceFlinger: try dropping features from EGL config query before giving up

Change-Id: I429ad841ef761dd9b036c6dca73b4af9337b277a