Fix CoreLib fast up-to-date check

Fixes dotnet#68698

CoreLib's fast up-to-date check was broken because the output pdb was
moved into a different folder. Changing this to use a copy task instead
and consolidate the two targets into one.

I couldn't find a publicly exposed property that allows to change the
pdb's output path, hence I decided to copy.

src/coreclr/Directory.Build.targets

@@ -2,36 +2,26 @@
   <Import Project="..\..\Directory.Build.targets" />
 
   <ItemGroup>
-    <BuiltBinary Include="$(TargetPath)" />
-    <_AllPdbs Include="@(BuiltBinary -> '%(RootDir)%(Directory)%(Filename).pdb')">
-      <FolderName>$([System.IO.Directory]::GetParent(`%(Identity)`).Name)</FolderName>
-    </_AllPdbs>
+    <_DebugSymbolToMove Include="@(DebugSymbolsProjectOutputGroupOutput->Metadata('FinalOutputPath'))"
+                        FolderName="$([System.IO.Directory]::GetParent('%(Identity)').Name)" />
+    <_DebugSymbolToMoveToExclude Include="@(_DebugSymbolToMove->WithMetadataValue('FolderName', 'aotsdk'))" />
+    <_DebugSymbolToMoveToUpdate Include="@(_DebugSymbolToMove)"
+                                Exclude="@(_DebugSymbolToMoveToExclude)" />
+    <!-- Remove the FolderName metadata for projects that don't reside under an aotsdk folder. -->
+    <_DebugSymbolToMove Update="@(_DebugSymbolToMoveToUpdate)"
+                        FolderName="" />
+    <_DebugSymbolToMove Update="@(_DebugSymbolToMove)"
+                        Destination="$(RuntimeBinDir)PDB\%(FolderName)\%(Filename)%(Extension)" />
   </ItemGroup>
 
-  <!-- Target used to consolidate all PDBs into a single location, except the aotsdk
-       PDBs, as S.P.C will overwrite the coreclr PDBs -->
+  <!-- Consolidate all PDBs into a single location, except the aotsdk PDBs, as S.P.C will overwrite the coreclr PDBs. -->
   <Target Name="MoveSymbolFiles"
-          AfterTargets="Build"
-          Condition="Exists(@(_AllPdbs))"
-          Inputs="@(_AllPdbs)"
-          Outputs="@(_AllPdbs -> '$(RuntimeBinDir)PDB/%(Filename).pdb')">
-
-    <Move SourceFiles="@(_AllPdbs)"
-          DestinationFolder="$(RuntimeBinDir)PDB"
-          Condition="'%(_AllPdbs.FolderName)' != 'aotsdk'" />
-
-  </Target>
-
-  <Target Name="MoveAotSymbolFiles"
-          AfterTargets="Build"
-          Condition="Exists(@(_AllPdbs))"
-          Inputs="@(_AllPdbs)"
-          Outputs="@(_AllPdbs -> '$(RuntimeBinDir)PDB/aotsdk/%(Filename).pdb')">
-
-    <Move SourceFiles="@(_AllPdbs)"
-          DestinationFolder="$(RuntimeBinDir)PDB/aotsdk"
-          Condition="'%(_AllPdbs.FolderName)' == 'aotsdk'" />
-
+          AfterTargets="CopyFilesToOutputDirectory"
+          Inputs="@(_DebugSymbolToMove)"
+          Outputs="@(_DebugSymbolToMove->Metadata('Destination'))">
+    <Copy SourceFiles="@(_DebugSymbolToMove)"
+          DestinationFiles="@(_DebugSymbolToMove->Metadata('Destination'))"
+          UseHardlinksIfPossible="false" />
   </Target>
 
   <!-- Import targets here to have TargetPath and other macros defined. Limit to CoreLib. -->

src/coreclr/System.Private.CoreLib/System.Private.CoreLib.csproj

@@ -9,7 +9,7 @@
     <TargetFramework>$(NetCoreAppCurrent)</TargetFramework>
 
     <!-- Force System.Private.CoreLib.dll into a special IL output directory -->
-    <OutputPath>$(RuntimeBinDir)/IL/</OutputPath>
+    <OutputPath>$(RuntimeBinDir)IL\</OutputPath>
     <Configurations>Debug;Release;Checked</Configurations>
     <Platforms>x64;x86;arm;arm64</Platforms>