vk_loader_settings.json with empty "stderr_log" and VK_LOADER_DEBUG=all generate partial log

[christophe-lunarg]

Three cases.

1. VK_LOADER_DEBUG is not set and stderr_log is set to error,warn,info,debug,layer,driver
   vk_loader_settings.json
   I am getting an exhaustive log:
   log.txt

2. VK_LOADER_DEBUG is set to 'all' and vk_loader_settings.json doesn't exist:
   log2.txt an expected different log, exhaustive.

3. VK_LOADER_DEBUG is set to 'all' and stderr_log is set to nothing:
   I am getting a very small log corresponding to what was loaded in vk_loader_settings.json but most of the log is not outputted. So the filtering in the Vulkan Loader doesn't seem consistent.
   log3.txt
   vk_loader_settings.json

[charles-lunarg]

Is this a duplicate of #1594?