Always read pixels from fbo in fbo recreate.no_rebind tests
Always read pixels from fbo in fbo recreate.no_rebind tests

Instead of rendering texture to screen and verifying result, read texture
attachments pixels using fbo. This changes texture tests to work same way as
renderbuffer tests work and avoids triggering some bugs in reference context.

Bug: 21526068
Change-Id: I3009703a947e1a11327cf8f49585dce2a3270a04

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