Revise WSI setup.

- Set up present queue creation correctly.
- Move WSI functions to VulkanTestContext.
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Review URL: https://codereview.chromium.org/1899213002
diff --git a/src/gpu/vk/GrVkGpu.cpp b/src/gpu/vk/GrVkGpu.cpp
index 040912e..eebb589 100644
--- a/src/gpu/vk/GrVkGpu.cpp
+++ b/src/gpu/vk/GrVkGpu.cpp
@@ -120,7 +120,7 @@
         VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO, // sType
         nullptr,                                    // pNext
         VK_COMMAND_POOL_CREATE_TRANSIENT_BIT,       // CmdPoolCreateFlags
-        backendCtx->fQueueFamilyIndex,              // queueFamilyIndex
+        backendCtx->fGraphicsQueueIndex,            // queueFamilyIndex
     };
     GR_VK_CALL_ERRCHECK(this->vkInterface(), CreateCommandPool(fDevice, &cmdPoolInfo, nullptr,
                                                                &fCmdPool));