Fix SupportedRuntimeIdentifiers substitution in Directory.Build.targe…

…ts.in. (#48022)

This fixes the native AOT template tests on Linux.

Directory.Build.props

@@ -161,23 +161,9 @@
   <PropertyGroup>
     <BuildArchitecture>$([System.Runtime.InteropServices.RuntimeInformation]::ProcessArchitecture.ToString().ToLowerInvariant())</BuildArchitecture>
 
-    <!-- This defines the list of RIDs supported by the ASP.NET Core shared framework. -->
-    <SupportedRuntimeIdentifiers>
-      win-x64;
-      win-x86;
-      win-arm;
-      win-arm64;
-      osx-x64;
-      osx-arm64;
-      linux-musl-x64;
-      linux-musl-arm;
-      linux-musl-arm64;
-      linux-x64;
-      linux-arm;
-      linux-arm64;
-      freebsd-x64
-    </SupportedRuntimeIdentifiers>
-
+    <!-- This defines the list of RIDs supported by the ASP.NET Core shared framework.
+         The list is a semicolon separated list of RIDs. Whitespace may not be added to the property. -->
+    <SupportedRuntimeIdentifiers>win-x64;win-x86;win-arm;win-arm64;osx-x64;osx-arm64;linux-musl-x64;linux-musl-arm;linux-musl-arm64;linux-x64;linux-arm;linux-arm64;freebsd-x64</SupportedRuntimeIdentifiers>
     <SupportedRuntimeIdentifiers Condition=" '$(PortableBuild)' == 'false' ">$(SupportedRuntimeIdentifiers);$(TargetRuntimeIdentifier)</SupportedRuntimeIdentifiers>
 
     <!-- Playwright provides binaries for Windows (x86 and x64), macOS (x64) and Linux (x64, non musl). We can't use it on other architectures. -->

eng/tools/GenerateFiles/GenerateFiles.csproj

@@ -26,7 +26,7 @@
         MicrosoftNETCoreAppRuntimeVersion=$(MicrosoftNETCoreAppRuntimeVersion);
         MicrosoftPlaywrightCLIVersion=$(MicrosoftPlaywrightCLIVersion);
         LibNetHostAppPackVersion=$(BundledNETCoreAppPackageVersion);
-        SupportedRuntimeIdentifiers=$(SupportedRuntimeIdentifiers.Trim());
+        SupportedRuntimeIdentifiers=$([MSBuild]::Escape($(SupportedRuntimeIdentifiers)));
         ArtifactsShippingPackagesDir=$(ArtifactsShippingPackagesDir)
       </_TemplateProperties>
     </PropertyGroup>