vulkan: fix vkinfo with layer extensions

vkinfo enable layers only when options.validate is true.  We should use
layer extensions, such as VK_EXT_debug_report, only when layers are
enabled.

Bug: 28317797
Change-Id: I02bb34b728f3f3072111444194ee97065e38e401
diff --git a/vulkan/tools/vkinfo.cpp b/vulkan/tools/vkinfo.cpp
index e97e5f5..066563a 100644
--- a/vulkan/tools/vkinfo.cpp
+++ b/vulkan/tools/vkinfo.cpp
@@ -162,8 +162,11 @@
     uint32_t num_extensions = 0;
     for (const auto& desired_ext : kDesiredExtensions) {
         bool available = HasExtension(info.extensions, desired_ext);
-        for (size_t i = 0; !available && i < info.layer_extensions.size(); i++)
-            available = HasExtension(info.layer_extensions[i], desired_ext);
+        if (options.validate) {
+            for (size_t i = 0; !available && i < info.layer_extensions.size();
+                 i++)
+                available = HasExtension(info.layer_extensions[i], desired_ext);
+        }
         if (available)
             extensions[num_extensions++] = desired_ext;
     }
@@ -236,8 +239,12 @@
     uint32_t num_extensions = 0;
     for (const auto& desired_ext : kDesiredExtensions) {
         bool available = HasExtension(info->extensions, desired_ext);
-        for (size_t i = 0; !available && i < info->layer_extensions.size(); i++)
-            available = HasExtension(info->layer_extensions[i], desired_ext);
+        if (options.validate) {
+            for (size_t i = 0; !available && i < info->layer_extensions.size();
+                 i++)
+                available =
+                    HasExtension(info->layer_extensions[i], desired_ext);
+        }
         if (available)
             extensions[num_extensions++] = desired_ext;
     }