FS-11288: [Build-System] Refactor WIX project to not miss modules in msi on slow machines. Move Windows build logic from legacy util.vbs to modern props. Fix sound packages improper extraction. Fix multiprocessor build under msbuild.

libs/win32/libav/libav.2017.vcxproj

@@ -24,6 +24,8 @@
     <WindowsTargetPlatformVersion>8.1</WindowsTargetPlatformVersion>
     <ProjectGuid>{841C345F-FCC7-4F64-8F54-0281CEABEB01}</ProjectGuid>
   </PropertyGroup>
+  <Import Project="$(SolutionDir)\w32\yasm.props" Condition=" '$(YasmPropsImported)' == '' " />
+  <Import Project="$(SolutionDir)\w32\download_libav.props" Condition=" '$(libavPropsImported)' == '' " />
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='release|Win32'" Label="Configuration">
     <ConfigurationType>StaticLibrary</ConfigurationType>
@@ -141,12 +143,6 @@
     <_ProjectFileVersion>10.0.30319.1</_ProjectFileVersion>
   </PropertyGroup>
   <ItemGroup>
-    <CustomBuild Include="cleancount">
-      <FileType>Document</FileType>
-      <Message>Downloading Yasm Modular Assembler (yasm.exe).</Message>
-      <Command>if not exist "$(SolutionDir)libs\yasm.exe" cscript /nologo "$(ProjectDir)..\util.vbs" GetYasmEXE "$(SolutionDir)libs\"</Command>
-      <Outputs>$(ProjectDir)yasm.exe;%(Outputs)</Outputs>
-    </CustomBuild>
     <ClCompile Include="..\..\libav\libavcodec\4xm.c" />
     <ClCompile Include="..\..\libav\libavcodec\8bps.c" />
     <ClCompile Include="..\..\libav\libavcodec\8svx.c" />
@@ -1642,9 +1638,6 @@
     </CustomBuild>
   </ItemGroup>
   <ItemGroup>
-    <ProjectReference Include="..\Download libav.2017.vcxproj">
-      <Project>{77c9e0a2-177d-4bd6-9efd-75a56f886325}</Project>
-    </ProjectReference>
     <ProjectReference Include="..\libx264\libx264.2017.vcxproj">
       <Project>{20179127-853b-4fe9-b7c0-9e817e6a3a72}</Project>
     </ProjectReference>