stubhal: add EnumeratePhysicalDeviceGroups

Since in VK1.1 loader VkPhysicalDeviceGroupProperties get queried by
calling vkEnumeratePhysicalDeviceGroups, the same stub function needs
to be added in stubhal. e.g. gce_x86_phone-userdebug_fastbuild3c_linux
is using stubhal.

Bug: b/72809176
Test: VulkanFeaturesTest
Test: adb shell cmd gpu vkjson
Change-Id: I16f9e5fd1cb8845edd3f1ef171af7942c671647f