loader: Properly filter ICD extensions
loader: Properly filter ICD extensions

As of NVIDIA driver 355.00.19, the ICD's CreateInstance
checks for invalid extension names and it turns out the
loader was passing on DEBUG_REPORT when it should have
been filtered out.
This change re-constructs the ICD's extension list to
do that filtering.

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools