Vulkan: correctly expose Vulkan entry points

This change fixes the advertisement of core Vulkan entry points as below:
1. GIPA returns a valid checked_proc for 1.1 core device APIs.
2. GDPA returns NULL for 1.1 core device APIs on a 1.0 physical device.

Bug: 134185757
Bug: 142266108
Test: dEQP-VK.memory.binding on 1.1 loader and 1.0 device ICD
Test: dEQP-VK.api.info.instance on 1.1 loader and 1.0 instance ICD
Change-Id: Ieb814516a4019f1a330178bfeb414e1450895c5c
Merged-In: I0a3e06dc04bade4f36a7e68ee2f53979c656ee4e