Add GenerateAndBuildOnly Option

[lihaMSFT]

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This PR adds an option to run toolchain generator and builder without actually executing the built binary.

This way we can attach other tools such as perfview and Visual Studio Performance Profiler to profile the benchmarks.

[dnfadmin]

All CLA requirements met.

[lihaMSFT]

Hello Adam,

VS Performance Profiler supports multiple types of profiling: CPU, instrumentation, object allocation and has a large API surface. We can discuss a potential integration in the future.

Thanks.