Expose EGL_KHR_no_config_context on more backends. EGL_KHR_no_config_context can be exposed on any backend that supports EGL_ANGLE_flexible_surface_compatibility Bug: chromium:1253930 Change-Id: Iec75ce944fc463a8c476579234be77028f74113b Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3190611 Reviewed-by: Peng Huang <penghuang@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>