Remove unused function from es31fSRGBDecodeTests.cpp am: 1ee59ff986 am: 2e80d40a0b am: 4e9833b13f am: 7935d416ee
Remove unused function from es31fSRGBDecodeTests.cpp am: 1ee59ff986 am: 2e80d40a0b am: 4e9833b13f
am: 7935d416ee

Change-Id: I2939c52a6b08e71518697c638a50d8a7299a5118

KhronosGroup/VK-GL-CTS,googlestadia/VK-GL-CTS,KhronosGroup/VK-GL-CTS,KhronosGroup/VK-GL-CTS,googlestadia/VK-GL-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/Vulkan-CTS,googlestadia/VK-GL-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/VK-GL-CTS,googlestadia/VK-GL-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/VK-GL-CTS,googlestadia/VK-GL-CTS,KhronosGroup/Vulkan-CTS,googlestadia/VK-GL-CTS,KhronosGroup/VK-GL-CTS