Fix initiazation bug in teglSwapBuffersWithDamage.cpp
Fix initiazation bug in teglSwapBuffersWithDamage.cpp

Add background initialization for the test case using buffer age

Change-Id: If8abea729208459f6bea872bcb4b25d7fb627e61

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