Add supports_legacy_dithering feature VK_EXT_legacy_dithering => VkPhysicalDeviceLegacyDitheringFeaturesEXT.legacyDithering => supportsLegacyDithering Now getting enabled=true on Android master. Bug: b/284462263 Change-Id: Ibf43184c78d9847044b10413d2050b653e452c9b Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4567572 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>