layers: Update ShaderChecker to use new logging mechanism
layers: Update ShaderChecker to use new logging mechanism

V2: Rebase, fix issues with log_msg args, delete more old junk.

Signed-off-by: Chris Forbes <5dcac483e7a6e31a5cbe89f38cc69dff8ee93dac@ijw.co.nz>

critsec/Vulkan-LoaderAndValidationLayers,elongbug/Vulkan-LoaderAndValidationLayers,Radamanthe/VulkanSamples,Radamanthe/VulkanSamples,sashinde/VulkanTools,elongbug/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,Radamanthe/VulkanSamples,KhronosGroup/Vulkan-LoaderAndValidationLayers,critsec/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,sashinde/VulkanTools,Radamanthe/VulkanSamples,critsec/Vulkan-LoaderAndValidationLayers,elongbug/Vulkan-LoaderAndValidationLayers,sashinde/VulkanTools,KhronosGroup/Vulkan-LoaderAndValidationLayers,critsec/Vulkan-LoaderAndValidationLayers,Radamanthe/VulkanSamples,Radamanthe/VulkanSamples,sashinde/VulkanTools,elongbug/Vulkan-LoaderAndValidationLayers