[NativeAOT-LLVM] Building for Win/Linux fails

[yowl]

While the branch is aimed to building LLVM/Wasm, it ought to be possible to still build for win-x64 and linux-x64 but attempting to do so fails with

E:\tmp\aot\pkg\microsoft.dotnet.ilcompiler.llvm\7.0.0-dev\build\Microsoft.NETCore.Native.Publish.targets(75,5): error : The PrivateSdkAssemblies ItemGroup is required for _ComputeAssembliesToCompileToNative [E:\tmp\aot\aot.csproj]

This is a similar problem to #260 (comment) , the names are

Message:  PackageDefinitions Microsoft.DotNet.ILCompiler.LLVM/7.0.0-dev PackageDefinitions.Name Microsoft.DotNet.ILCompiler.LLVM RuntimeIlcPackageName runtime.win-x64.Microsoft.DotNet.ILCompiler

and can be worked around by modifying Microsoft.DotNet.ILCompiler.targets to append .LLVM to the package name, for example, just handling both names

      <RuntimePackagePath Condition="'%(PackageDefinitions.Name)' == '$(RuntimeIlcPackageName)'">%(PackageDefinitions.ResolvedPath)</RuntimePackagePath>
      <RuntimePackagePath Condition="'%(PackageDefinitions.Name)' == '$(RuntimeIlcPackageName).LLVM'">%(PackageDefinitions.ResolvedPath)</RuntimePackagePath>
      <IlcHostPackagePath Condition="'%(PackageDefinitions.Name)' == '$(IlcHostPackageName)'">%(PackageDefinitions.ResolvedPath)</IlcHostPackagePath>
      <IlcHostPackagePath Condition="'%(PackageDefinitions.Name)' == '$(IlcHostPackageName).LLVM'">%(PackageDefinitions.ResolvedPath)</IlcHostPackagePath>