Fix EGL config incompatibility in negative_partial_update tests
Fix EGL config incompatibility in negative_partial_update tests

Choosing 2 separate EGL configs, one for a window and a different one for
a pbuffer surface doesn't guarantee that those configs are compatible.
The dummyPbuffer surface may use different bit depths than the window
surface. This causes an unintended failure in eglMakeCurrent().

Choose a single EGL config suitable for both: the window and the pbuffer,
if both are being used.

Components: EGL
VK-GL-CTS issue: 2037
Affects: dEQP-EGL.functional.negative_partial_update.*

Change-Id: I676f760cbe2df3c906c376304efefa3170760438
Signed-off-by: Tomek Bury <eae99321e301c98453775b9b6ada472ca7b65f3e@broadcom.com>

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