Change primitives to build platform specific (#10078)

If just building AnyCPU only the x86 transport package gets the runtime
assembly. Rather than work around that, build explicitly for each
platform so WindowsDesktop can get what it needs.

Author: JeremyKuhne

Microsoft.Dotnet.Wpf.sln

@@ -1615,18 +1615,18 @@ Global
 		{D5A55FFC-E408-4BC5-B633-1CBBE9A94DE1}.Release|x64.Build.0 = Release|x64
 		{D5A55FFC-E408-4BC5-B633-1CBBE9A94DE1}.Release|x86.ActiveCfg = Release|x86
 		{D5A55FFC-E408-4BC5-B633-1CBBE9A94DE1}.Release|x86.Build.0 = Release|x86
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|arm64.ActiveCfg = Debug|Any CPU
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|arm64.Build.0 = Debug|Any CPU
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|x64.ActiveCfg = Debug|Any CPU
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|x64.Build.0 = Debug|Any CPU
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|x86.Build.0 = Debug|Any CPU
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|arm64.ActiveCfg = Release|Any CPU
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|arm64.Build.0 = Release|Any CPU
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|x64.ActiveCfg = Release|Any CPU
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|x64.Build.0 = Release|Any CPU
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|x86.ActiveCfg = Release|Any CPU
-		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|x86.Build.0 = Release|Any CPU
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|arm64.ActiveCfg = Debug|arm64
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|arm64.Build.0 = Debug|arm64
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|x64.ActiveCfg = Debug|x64
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|x64.Build.0 = Debug|x64
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|x86.ActiveCfg = Debug|x86
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Debug|x86.Build.0 = Debug|x86
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|arm64.ActiveCfg = Release|arm64
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|arm64.Build.0 = Release|arm64
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|x64.ActiveCfg = Release|x64
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|x64.Build.0 = Release|x64
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|x86.ActiveCfg = Release|x86
+		{5306FA93-178C-4535-ADEE-86B1DE1B68CB}.Release|x86.Build.0 = Release|x86
 		{0EFFC7C4-B486-4852-8CED-EDEB46E02C42}.Debug|arm64.ActiveCfg = Debug|Any CPU
 		{0EFFC7C4-B486-4852-8CED-EDEB46E02C42}.Debug|arm64.Build.0 = Debug|Any CPU
 		{0EFFC7C4-B486-4852-8CED-EDEB46E02C42}.Debug|x64.ActiveCfg = Debug|Any CPU

src/Microsoft.DotNet.Wpf/src/System.Windows.Primitives/System.Windows.Primitives.csproj

@@ -5,7 +5,7 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <CLSCompliant>false</CLSCompliant>
     <Nullable>enable</Nullable>
-    <Platforms>AnyCPU</Platforms>
+    <Platforms>x86;x64;arm64</Platforms>
 
     <!--
       We align casing and naming with Win32 API. As such some types have all lower case names, which
@@ -16,7 +16,6 @@
     <NoWarn>$(NoWarn);CS8981;CS3016</NoWarn>
 
     <Deterministic>true</Deterministic>
-    <ProduceReferenceAssembly>true</ProduceReferenceAssembly>
     <UsePublicApiAnalyzers>true</UsePublicApiAnalyzers>
     <RootNamespace />
     <DefaultItemExcludes>$(DefaultItemExcludes);ref\**</DefaultItemExcludes>