layers: Fix uses of KHR ifdef to KHX in objecttracker
layers: Fix uses of KHR ifdef to KHX in objecttracker

In a few places, we were using VK_USE_PLATFORM_WIN32_KHR instead of
VK_USE_PLATFORM_WIN32_KHX.

Change-Id: I579ea848868396b9c2877e43ca24780476e55919

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