All texture formats, except YUV or sRGB formats, now have access
to the floating point path for texture filtering. High precision
filtering can be enabled using:
glHint(GL_TEXTURE_FILTERING_HINT_CHROMIUM, GL_NICEST)

Bug swiftshader:76

Change-Id: Iabbe86d1bbf43070bfc5f61254c101a75c744401
Reviewed-on: https://swiftshader-review.googlesource.com/10808Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>