vulkan-cereal: Improve build with g++

- Add missing template type
- Add missing variable assignment character
- Fix gMock build


BUG=b:202522444
TEST=compile

Change-Id: Id76e7fed4af5e53766f22e8eb0d1b2aa91824ebc
diff --git a/stream-servers/tests/DisplayVk_unittest.cpp b/stream-servers/tests/DisplayVk_unittest.cpp
index 1f01bc9..41b9597 100644
--- a/stream-servers/tests/DisplayVk_unittest.cpp
+++ b/stream-servers/tests/DisplayVk_unittest.cpp
@@ -178,7 +178,7 @@
     void createLogicalDevice() {
         const float queuePriority = 1.0f;
         std::vector<VkDeviceQueueCreateInfo> queueCis(0);
-        for (auto queueFamilyIndex : std::unordered_set(
+        for (auto queueFamilyIndex : std::unordered_set<uint32_t>(
                  {m_swapChainQueueFamilyIndex, m_compositorQueueFamilyIndex})) {
             VkDeviceQueueCreateInfo queueCi = {
                 .sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO,