chore: Remove unneeded project reference from auto-generated project

[filzrev]

This PR remove ProjectReference of benchmark project from BenchmarkDotNet.Autogenerated.csproj

CsProjGenerator gather referenced dlls of benchmark project.
Then add referenced dlls as <Reference Include="..." /> node.

So original <ProjectReference Include="..." /> node is not expected to be used when building BenchmarkDotNet.Autogenerated.csproj

Test
This code path is not used when running IntegrationTest project or when using non Release custom configuration.

BenchmarkDotNet/src/BenchmarkDotNet/Toolchains/DotNetCli/DotNetCliCommand.cs

Line 57 in bcdcc98

public async Task<BuildResult> RestoreThenBuildAsync(CancellationToken cancellationToken = default)

So I've confirmed behavior by using generated binlog.
After this PR content is merged. Reference project evaluation stage is skipped on local build.

[timcassell]

When I tried it originally the disassemble tests failed. Maybe that was fixed with clrmd v4. [Edit] Actually, I see the tests are still failing on arm.