Fix framework device properties generated code

Fix framework device properties generated code

The gen_framework.py scripts had a few issues:

1) Generated code for non-physical device proprties functions.

2) Failed to generate correct code when it couldn't determine
the actual name of the extension.

3) Generated code that caused core physical device properties,
not part of an extension, to not be filled in.

Affects:

dEQP-VK.* (only initialization)

Components: Framework, Vulkan

VK-GL-CTS issue: 2425

Change-Id: I267eddc86317440007423f73a4744e14eee11ff6