v2: - Require EGL_KHR_surfaceless_context instead of other surfaceless
      extensions.
    - Fix for-loop typo.
    - Make EGL_KHR_create_context_setup take a renderable_type_mask argument.
    - Make EGL_KHR_create_context_setup return whether it succeeded.
    - PIGLIT_SKIP if eglChooseConfig fails (in the case of requesting an
      ES 1.x context when 1.x isn't supported).
    - Add version_is_valid_for_context helper function.