loader: gh1449 - Fix mem leak on CTS
loader: gh1449 - Fix mem leak on CTS

Fix a memory leak in the CTS test which fails randomly during
the vkCreateInstance call.

Change-Id: Ie72feac730d3854cb2af9e13a3687aa43081bfd5

KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers