If VkSampleLocationsInfoEXT::sampleLocationsPerPixel is 0, the validation layers message will say Unhandled VkSampleCountFlagBits
Full message is:
vkCmdSetSampleLocationsEXT(): pSampleLocationsInfo->sampleLocationsPerPixel is Unhandled VkSampleCountFlagBits, but VkPhysicalDeviceSampleLocationsPropertiesEXT::sampleLocationSampleCounts is VK_SAMPLE_COUNT_1_BIT|VK_SAMPLE_COUNT_2_BIT|VK_SAMPLE_COUNT_4_BIT|VK_SAMPLE_COUNT_8_BIT|VK_SAMPLE_COUNT_16_BIT.
We should have a way to print the invalid value in string_VkSampleCountFlagBits