Fix VulkanUnitTests on Visual Studio

Also copy the DLLs to build/
This makes it consistent with the CMake build.

Bug b/116336664
Bug b/29024574

Change-Id: I747a52383492c3ec5493f1a232cbbf5c98aec219
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/27608
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
diff --git a/src/Vulkan/vulkan.vcxproj b/src/Vulkan/vulkan.vcxproj
index 06be317..bb3fa49 100644
--- a/src/Vulkan/vulkan.vcxproj
+++ b/src/Vulkan/vulkan.vcxproj
@@ -74,7 +74,10 @@
     </Link>

     <PostBuildEvent>

       <Command>mkdir "$(SolutionDir)out\$(Configuration)_$(Platform)\"

-copy "$(OutDir)vk_swiftshader.dll" "$(SolutionDir)out\$(Configuration)_$(Platform)\"</Command>

+mkdir "$(SolutionDir)build\$(Configuration)_$(Platform)\"

+copy "$(OutDir)vk_swiftshader.dll" "$(SolutionDir)out\$(Configuration)_$(Platform)\"

+copy "$(OutDir)vk_swiftshader.dll" "$(SolutionDir)build\$(Configuration)_$(Platform)\"

+IF EXIST "$(SolutionDir)..\deqp" (copy "$(OutDir)vk_swiftshader.dll" "$(SolutionDir)..\deqp\build\external\vulkancts\modules\vulkan\vulkan-1.dll")</Command>

     </PostBuildEvent>

   </ItemDefinitionGroup>

   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">

@@ -94,7 +97,10 @@
     </Link>

     <PostBuildEvent>

       <Command>mkdir "$(SolutionDir)out\$(Configuration)_$(Platform)\"

-copy "$(OutDir)vk_swiftshader.dll" "$(SolutionDir)out\$(Configuration)_$(Platform)\"</Command>

+mkdir "$(SolutionDir)build\$(Configuration)_$(Platform)\"

+copy "$(OutDir)vk_swiftshader.dll" "$(SolutionDir)out\$(Configuration)_$(Platform)\"

+copy "$(OutDir)vk_swiftshader.dll" "$(SolutionDir)build\$(Configuration)_$(Platform)\"

+IF EXIST "$(SolutionDir)..\deqp" (copy "$(OutDir)vk_swiftshader.dll" "$(SolutionDir)..\deqp\build\external\vulkancts\modules\vulkan\vulkan-1.dll")</Command>

     </PostBuildEvent>

   </ItemDefinitionGroup>

   <ItemGroup>