Support GL_EXT_texture_sRGB_R(G)8 extensions in fbo completeness tests.
Support GL_EXT_texture_sRGB_R(G)8 extensions in fbo completeness tests.

Change-Id: Ic91c8106f63848c0f960af45b75a55f62a2d107e

KhronosGroup/VK-GL-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/Vulkan-CTS,googlestadia/VK-GL-CTS,chadversary/deqp,KhronosGroup/VK-GL-CTS,geekboxzone/mmallow_external_deqp,geekboxzone/mmallow_external_deqp,KhronosGroup/VK-GL-CTS,KhronosGroup/VK-GL-CTS,geekboxzone/mmallow_external_deqp,geekboxzone/mmallow_external_deqp,KhronosGroup/VK-GL-CTS,KhronosGroup/Vulkan-CTS,chadversary/deqp,KhronosGroup/Vulkan-CTS,chadversary/deqp,geekboxzone/mmallow_external_deqp,KhronosGroup/Vulkan-CTS,KhronosGroup/VK-GL-CTS,googlestadia/VK-GL-CTS,googlestadia/VK-GL-CTS,chadversary/deqp,geekboxzone/mmallow_external_deqp,googlestadia/VK-GL-CTS,googlestadia/VK-GL-CTS,googlestadia/VK-GL-CTS,chadversary/deqp,chadversary/deqp,KhronosGroup/Vulkan-CTS