update_external_sources: Get Windows LunarGLASS build working again
update_external_sources: Get Windows LunarGLASS build working again

Include the following changes:
- Enable SPIR-V rev 32 support
- Always delete previous LunarGLASS builds, just like glslang
- Disable Debug LunarGLASS build
- Change order of glslang build so that Release resides in install

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