fix the CI (#2079)

* set ErrorOnDuplicatePublishOutputFiles to false to stop getting "error NETSDK1152: Found multiple publish output files with the same relative path" about "xunit.runner.json" files

* we can't target net6.0 and use .NET 7 ILCompiler anymore (#2080)

src/BenchmarkDotNet/Toolchains/NativeAot/Generator.cs

@@ -137,6 +137,7 @@ private string GenerateProjectForNuGetBuild(BuildPartition buildPartition, Artif
     <IlcGenerateCompleteTypeMetadata>{ilcGenerateCompleteTypeMetadata}</IlcGenerateCompleteTypeMetadata>
     <IlcGenerateStackTraceData>{ilcGenerateStackTraceData}</IlcGenerateStackTraceData>
     <EnsureNETCoreAppRuntime>false</EnsureNETCoreAppRuntime> <!-- workaround for 'This runtime may not be supported by.NET Core.' error -->
+    <ErrorOnDuplicatePublishOutputFiles>false</ErrorOnDuplicatePublishOutputFiles> <!-- workaround for 'Found multiple publish output files with the same relative path.' error -->
     <ValidateExecutableReferencesMatchSelfContained>false</ValidateExecutableReferencesMatchSelfContained>
     {GetInstructionSetSettings(buildPartition)}
   </PropertyGroup>

tests/BenchmarkDotNet.IntegrationTests/NativeAotTests.cs

@@ -23,6 +23,8 @@ public void LatestNativeAotVersionIsSupported()
                 return;
             if (ContinuousIntegration.IsAppVeyorOnWindows()) // too time consuming for AppVeyor (1h limit)
                 return;
+            if (NativeAotRuntime.GetCurrentVersion().RuntimeMoniker < RuntimeMoniker.NativeAot70) // we can't target net6.0 and use .NET 7 ILCompiler anymore (#2080)
+                return;
 
             var toolchain = NativeAotToolchain.CreateBuilder().UseNuGet().IlcInstructionSet(IsAvx2Supported() ? "avx2" : "").ToToolchain();