Remove ServiceProviderMode in DI Perf tests

Today, we have an option to a lot of our DI perf tests to take the provider "Mode":

https://github.com/dotnet/performance/blob/165811e59433b99e693a29da8b67b223fce6fc26/src/benchmarks/micro/libraries/Microsoft.Extensions.DependencyInjection/TimeToFirstServiceBenchmark.cs#L21-L32

However, this doesn't work because:

1. We don't have InternalsVisibleTo working for our perf tests
2. With https://github.com/dotnet/runtime/pull/52140, even if someone tried compiling with IVT the code wouldn't work anymore because of the internal refactoring.

We should just remove these ServiceProviderModes from our tests. All they are doing is cluttering the results and not providing any other value, since the same test is getting executed 4 times.

When, in the future, we decide to really make this work, we can add the modes back. But until then, we should just remove them.

cc @davidfowl @maryamariyan @pakrym