layers: Capture device features from extension

layers: Capture device features from extension

When the VK_KHR_get_physical_device_properties2 is present, physical
device properties can be passed to VkCreate either in the
pEnabledFeatures member or VkDeviceCreateInfo or in a
VkPhysicalDeviceFeatures2KHR structure on the pNext chain.

Neither the parameter validation or core validation layers were
capturing device features from the pNext struct, causing false
parameter checking errors, when the default (all false) state was
used for later validations.

Change-Id: I187827443f09aafaa80588a78bc5b67595d0acda