Fix output for missing Vulkan surface extensions

When the Vulkan loader is present but there are no required surface
extensions, as will for example happen with the Null platform, glfwinfo
caused an error in glfwGetPhysicalDevicePresentationSupport and produced
confusing output.

tests/glfwinfo.c

@@ -954,14 +954,17 @@ int main(int argc, char** argv)
             uint32_t qfp_count;
             vkGetPhysicalDeviceQueueFamilyProperties(pd[i], &qfp_count, NULL);
 
-            printf("Vulkan device queue family presentation support:\n");
-            for (uint32_t j = 0;  j < qfp_count;  j++)
+            if (re)
             {
-                printf(" %u: ", j);
-                if (glfwGetPhysicalDevicePresentationSupport(instance, pd[i], j))
-                    printf("supported\n");
-                else
-                    printf("no\n");
+                printf("Vulkan device queue family presentation support:\n");
+                for (uint32_t j = 0;  j < qfp_count;  j++)
+                {
+                    printf(" %u: ", j);
+                    if (glfwGetPhysicalDevicePresentationSupport(instance, pd[i], j))
+                        printf("supported\n");
+                    else
+                        printf("no\n");
+                }
             }
 
             if (list_extensions)