opengles emulator: fix bugs in CUBE_MAP implementation in GLES_CM

We save the texData->target in original format, but use our internal format
(using GLTextureTargetToLocal) to make sure we're not mixing 2D and CUBE_MAP textures on
glBindTexture.
Also added the GL_S/R/T/Q constants where needed.
This fixes the Cube Map test in Api Demos.

Change-Id: Id5de45581f2227fe0978d7982a147cb6b4b595c4
5 files changed