Allow easier overriding of crossgen tasks/targets (#52021)

- Remove `ResolveReadyToRunCompilers` from `Microsoft.NET.Publish.targets`. This was always overriding (and identical to) the one in Microsoft.NET.CrossGen.targets
- Add properties for `CrossGenTargetsPath` and `CrossGenTasksPath` that can be set to import a different targets file and use a different task assembly. This is more in line with what we do for ILLink and should allow simplification of how dotnet/runtime uses in-repo crossgen targets in dotnet/runtime

Author: elinor-fung

src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.CrossGen.targets

@@ -35,6 +35,10 @@ Copyright (c) .NET Foundation. All rights reserved.
     <PublishReadyToRunEmitSymbols Condition="'$(PublishReadyToRunEmitSymbols)' == '' and $(RuntimeIdentifier.StartsWith('osx-'))">false</PublishReadyToRunEmitSymbols>
   </PropertyGroup>
 
+  <PropertyGroup>
+    <CrossGenTasksPath Condition="'$(CrossGenTasksPath)' == ''">$(MicrosoftNETBuildTasksAssembly)</CrossGenTasksPath>
+  </PropertyGroup>
+
   <!--
     ============================================================
                                         PrepOptimizer
@@ -386,7 +390,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     Prepare build for ReadyToRun compilations. Builds list of assemblies to compile, and computes paths to ReadyToRun compiler bits
     ============================================================
     -->
-  <UsingTask Condition="'$(Crossgen2TasksOverriden)' != 'true'" TaskName="PrepareForReadyToRunCompilation" AssemblyFile="$(MicrosoftNETBuildTasksAssembly)" />
+  <UsingTask Condition="'$(Crossgen2TasksOverriden)' != 'true'" TaskName="PrepareForReadyToRunCompilation" AssemblyFile="$(CrossGenTasksPath)" />
   <Target Name="_PrepareForReadyToRunCompilation" DependsOnTargets="ResolveReadyToRunCompilers;_ComputeManagedRuntimePackAssemblies;_ComputeAssembliesToPostprocessOnPublish">
 
     <PropertyGroup>
@@ -453,7 +457,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     </ItemGroup>
   </Target>
 
-  <UsingTask Condition="'$(Crossgen2TasksOverriden)' != 'true'" TaskName="ResolveReadyToRunCompilers" AssemblyFile="$(MicrosoftNETBuildTasksAssembly)" />
+  <UsingTask Condition="'$(Crossgen2TasksOverriden)' != 'true'" TaskName="ResolveReadyToRunCompilers" AssemblyFile="$(CrossGenTasksPath)" />
   <Target Name="ResolveReadyToRunCompilers">
     <ResolveReadyToRunCompilers RuntimePacks="@(ResolvedRuntimePack)"
                                 Crossgen2Packs="@(ResolvedCrossgen2Pack)"
@@ -476,7 +480,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     Compiles assemblies in the _ReadyToRunCompileList list into ReadyToRun images
     ============================================================
     -->
-  <UsingTask Condition="'$(Crossgen2TasksOverriden)' != 'true'" TaskName="RunReadyToRunCompiler" AssemblyFile="$(MicrosoftNETBuildTasksAssembly)" />
+  <UsingTask Condition="'$(Crossgen2TasksOverriden)' != 'true'" TaskName="RunReadyToRunCompiler" AssemblyFile="$(CrossGenTasksPath)" />
   <Target Name="_CreateR2RImages"
           Inputs="$(MSBuildAllProjects);@(_ReadyToRunCompileList);@(_ReadyToRunCompositeBuildInput);@(_ReadyToRunPgoFiles)"
           Outputs="%(_ReadyToRunCompileList.OutputR2RImage);%(_ReadyToRunCompileList.OutputPDBImage)">

src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets

@@ -411,22 +411,6 @@ Copyright (c) .NET Foundation. All rights reserved.
     </Copy>
   </Target>
 
-  <UsingTask TaskName="ResolveReadyToRunCompilers" AssemblyFile="$(MicrosoftNETBuildTasksAssembly)" />
-  <Target Name="ResolveReadyToRunCompilers">
-    <ResolveReadyToRunCompilers RuntimePacks="@(ResolvedRuntimePack)"
-                                Crossgen2Packs="@(ResolvedCrossgen2Pack)"
-                                TargetingPacks="@(ResolvedTargetingPack)"
-                                RuntimeGraphPath="$(RuntimeIdentifierGraphPath)"
-                                NETCoreSdkRuntimeIdentifier="$(NETCoreSdkRuntimeIdentifier)"
-                                EmitSymbols="$(PublishReadyToRunEmitSymbols)"
-                                ReadyToRunUseCrossgen2="$(PublishReadyToRunUseCrossgen2)"
-                                PerfmapFormatVersion="$(PublishReadyToRunPerfmapFormatVersion)">
-
-      <Output TaskParameter="CrossgenTool" ItemName="CrossgenTool" />
-      <Output TaskParameter="Crossgen2Tool" ItemName="Crossgen2Tool" />
-    </ResolveReadyToRunCompilers>
-  </Target>
-
   <!--
     ============================================================
                                         _ComputeResolvedFilesToPublishTypes

src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets

@@ -1370,14 +1370,18 @@ Copyright (c) .NET Foundation. All rights reserved.
     <ProjectCapability Remove="ReferenceManagerAssemblies" />
   </ItemGroup>
 
+  <PropertyGroup>
+    <CrossGenTargetsPath Condition="'$(CrossGenTargetsPath)' == ''">$(MSBuildThisFileDirectory)Microsoft.NET.CrossGen.targets</CrossGenTargetsPath>
+  </PropertyGroup>
+
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.Sdk.SourceLink.targets" Condition="'$(SuppressImplicitGitSourceLink)' != 'true'" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.DisableStandardFrameworkResolution.targets" Condition="'$(DisableStandardFrameworkResolution)' == 'true'" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.DesignerSupport.targets" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.GenerateAssemblyInfo.targets" Condition="'$(UsingNETSdkDefaults)' == 'true'"/>
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.GenerateGlobalUsings.targets" Condition="'$(Language)' == 'C#'"/>
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.GenerateSupportedRuntime.targets" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.ComposeStore.targets" Condition="'$(UsingNETSdkDefaults)' == 'true'" />
-  <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.CrossGen.targets" />
+  <Import Project="$(CrossGenTargetsPath)" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.ObsoleteReferences.targets" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.Publish.targets" />
   <Import Project="$(MSBuildThisFileDirectory)Microsoft.NET.PackStubs.targets" Condition="('$(Language)' == 'C++' and '$(_EnablePackageReferencesInVCProjects)' != 'true')"/>