Run benchmarks against musl

[jszwedko]

We should expand the CI benchmark job to run using musl as well to compare with glibc performance as Luke mentioned we saw differences here before with the allocator. We are also curious if musl performance ever becomes comparable with glibc performance for us and we can drop the glibc builds.

[MOZGIII]

I started with this, and pretty quickly hit the complication: benches are not adopted for our cross-compilation machinery, and it will take some extra steps to make them work right (not too much though). The alternative - going around our currently existing cross-compilation machinery - doesn't seem very productive, as we'll be reinventing the wheel.

Due to this, I'm bumping the estimate for this task.

[bruceg]

Closing since the benchmark workflow was deleted. Ref #6829

[jszwedko]

I actually think this one is still relevant as something we could do with the new regression suite (same with benchmarking different architectures and thread counts).